The first time I heard about this phrase, it is used by Prof Z about some work by Prof B. It is half joking, half disapproval. One either needs to painstakingly verify lots of details, or one can wave ones' way out. Through my academic career, I have seen many handwaver, but also more solid prover.
What should I say? The handwaver usually are better at convince an idea, a desire, a plan, which is most of the time what the reader want. The next step is for the reader to believe or not. If the reader know it must be true, no doubt about it, so fine, we can skip the verification step. The prover, taking much more pain, to show all things works, but people usually just glance over without even bother to read or follow.
What should I be? I cannot be 100% prover. I will knowingly leave a gap, a jumpable gap, not requiring to use your wing-of-belief to fly over, just for the sake of speed. Since I don't have much time. Then, should the proof be considered as finished? For the sake of writing the paper and submit it, yes. For the sake of understanding how it works, maybe not.
So, the answer is no. You should write a clear statement with a clear proof. Put doubt and confusion in the world is negative contribution.