(nonce word) Grumpy, ill-tempered.

Is Uffish a noun verb adjective or adverb?

uffishadjective. grumpy, ill-tempered.

Is Uffish an onomatopoeia?

This is what the OED has: according to it, uffish is an alternate spelling of huffish, and it has a few examples to back that up. And huffish, which means “arrogant” or “insolent”, comes from huff, which traces back to gusty onomatopoeia and its metaphorical use to characterize a mofette of mood.