We ran into the NYC rapper Tuesday in his hometown, and when we told him about Fiddy teasing his efforts to put together a Tekashi flick -- centered on all the snitching -- he seemed a little uneasy. But then, he got real ... and kinda craps on the idea of the movie.

Skinny says there are people's lives that are literally being ruined by the trial of 2 Nine Trey Bloods, and points out their families are being affected too. In other words, this isn't a game -- and certainly not something to be taken advantage of for financial gain.

For the record, Fifty's only made a passing comment about a potential Tekashi movie on social media.

Someone recently asked if it was true he was producing the film, and he said ... "I'm working boy."

BTW, Skinny's always been a sympathizer with Tekashi and the Treyway crew -- even if he's not affiliated with them -- and you can tell he feels for those who've already been convicted, like Shotti.