What does "competent" in a language actually mean?

Here's the thing: there is no standard, and the only thing that really matters is what the people reading your resume think. If you say you're fluent, you run the slight risk of pissing off someone who has worked hard to be able to speak better than you. If you say "competent" "conversant" "proficient", whatever, you run the risk of sounding like you took two years of high school spanish and have successfully vacationed in Mexico. If you can find out what the jobs you're looking for need/want, I'd tailor my resume for each application.

Competent means sufficiently capable. You may be surprised, I've worked with some amazingly incompetent people that got their jib based on their Spanish ability. One guy got hired because he lived in Costa Rica 11 years. Guess what? He spoke 11 words of Spanish! He was also awful at his job for other reasons, but I digress. The point is you can fool many people into believing you are competent. Is this a good thing? Maybe no, maybe yes. I got a job working through Latin America with no Spanish skills whatsoever. I did well. Of course I had translators and later when I was somewhat proficient it worked well. People appreciated the effort. I was like the bumblebee that flew without knowing that he shouldn't be able to. Now later, I got a job working for a native Spanish speaker and he and I had some serious personality clashes. The language skills that previously suited me just fine became a source of incompetence in new manager's eyes. I always felt him judging my Spanish and guess what again? I choked whenever I was in front of him. To this day he has no idea how well I spoke Spanish. I eventually got fired for this and other problems resulting from our "personality clash". It's true that when I was with him and surrounded by 3 native speakers not making concessions as 256 states, I floundered. Also, there truly was a limit to the tolerance of native speakers and my skills. There reached a point where I was just good enough that my efforts were no longer endearing. At a certain point I would meet new business connections and to them I became the guy that just spoke well enough to not be considered as trying really hard but the gringo that spoke shitty Spanish. It's a weird middle ground between being a beginner and somewhat advanced. I guess the bottom line is people can succeed with varying levels of competency depending on the context. Be careful what you commit to. You may get in over your head. At the same time you may have an awesome opportunity to improve your Spanish. If you don't promote your skills you won't get the interview. I say be confident and go for it. They should try your skills out in an interview. They will either weed you out or not. Suerte!

If you don't care for the CEFR scale, you can see if the http://en.wikipedia.org/wiki/ILR_scale scale is more helpful.

Your Spanish seems slightly better than my German. "Working proficiency" is the phrase, I think, you are looking for. I write on my CV: Languages: English (mother tongue), Swedish (complete fluency), German (working proficiency).

I've worked as a translator/interpreter and I agree with http://ask.metafilter.com/258237/What-does-competent-in-a-language-actually-mean#3752088 but would like to add that there are certain professions (technology, medicine, etc) where technical terms constitute up to 90% of important communication so it's ok to be much less proficient if you know all the latin-based terms. I would also like to add that if your reading comprehension is as good as reading a novel at near native speed, it will take you no more than a couple months to get equally as good at speaking, and even a couple weeks will likely make a huge difference. You have the base, you just need the immersion. Don't get discouraged by the occasional hard-to-understand person. The "every so often" aspect should tell you that it is the exception rather than the rule. My personal vote is that you can use "competent" on your application.

The http://en.wikipedia.org/wiki/Common_European_Framework_of_Reference_for_Languages might be useful.

Don't undersell yourself. Reading full-length novels - especially as long as Harry Potter - as fast as you would in your native language is quite a feat. My own experience reflects the suggestions of commenters above. At one point I had "competent" on my resumé and was advised by a recruiter-mentor to remove it. She asked me the same kinds of questions posed by the people above. Some versions now say "Language skills: Spanish..." and other say "Fluent in Spanish..."'. Highlighting other foreign language activities (e.g. study abroad, volunteer experience) can cement the fact that you have the skills needed. If Spanish skills are that important to the job, they will ask further details or your interview will be (partly) in Spanish.

I usually break down my skills. Because I can read 95% of non-specialzed Spanish with ease and can write pretty well but I don't think my speakng skills are quite enough for professional use. It hasn't been an issue since anytime they wanted those skills you really needed to be fluent which is a much higher skillset.

Can you take some sort of test? That might be easiest, and although I tend to dislike most language tests that claim to judge your actual language abilities (the TOEFL is an exception in my eyes because it has writing and speaking included), it adds credibility to your resumé. I once applied for a job with the Goethe Institute in Tokyo and they refused me because they didn't believe my Japanese was good enough. I then took the highest level Japanese Proficiency Language Test (N1) and passed. The whole test is a joke - it's multiple choice and basically only tests obscure grammar and kanji, and some ridiculously easy listening part which ironically, most people seem to find harder than the kanji part (I know people who passed it and can't even stutter their name in Japanese), but I can now claim that I have the certificate. (Now of course, if the person looking at my resumé knows the test is a joke...) I guess after all, it depends on whoever reads your resumé. The guy who refused me probably had several candidates before who claimed they were fluent in Japanese but actually weren't. Maybe someone else would have hired me and not even noticed if I didn't speak Japanese at all. It's a stupid system, but we have to work with it, so a test may really be your safest bet. If not, I agree with the above poster: state your fluency in categories like reading - speaking - listening etc. Some questionnaires I've had to fill in do this as well, so it's not that uncommon.