I had a similar experience in SO, I used the term "the most bulletproof-y way I can think of" or something like that in my answer, definitely used "bulletproof-

I had a similar experience in SO, I used the term "the most bulletproof-y way I can think of" or something like that in my answer, definitely used "bulletproof-y." Someone responded with something like "You shouldn't say that. Nothing's really bulletproof, you know."