A sort of adjective/participle/verb phrase. To be "big on" something is to like it, be a fan of it, etc.
If you're a propenent of something, you're also big on it.
Synonyms for big on
On this page, you will find 30 slang terms related to big on. Some of the top words include: hugified, ookii, dig, I would _____ to _____, off da spindle, and 25 more.