Adjectives

(s)prettypleasing by delicacy or grace; not imposing“pretty girl”, “pretty song”, “pretty room”
(s)pretty(used ironically) unexpectedly bad“a pretty mess”, “a pretty kettle of fish”

Adverbs

(r)reasonably, moderately, pretty, jolly, somewhat, fairly, middling, passablyto certain extent or degree“pretty big”, “pretty bad”, “jolly decent of him”, “the shoes are priced reasonably”, “he is fairly clever with computers”