Synonyms for Peachy:

adj.

wonderful (adjective)
excellent, dandy.

n.

excellent, incredible, wonder, exceptional, tremendous, decent. chalky, fruity, floury, fishy, buttery, chocolatey, chocolate, flowery, cheesy, gamey. peachy (noun)
cracking, dandy, nifty, groovy, slap-up, great, neat, bang up, smashing, good, bully, corking, not bad, swell, keen.

Other synonyms:

bang-up
bang up.
Other relevant words:
bully, exceptional, excellent.