as an adjective, 'pretty' describes something or someone as attractive in a delicate or endearing way.
She wore a pretty dress to the party.
The garden looks pretty in the springtime.
He gave her a pretty bouquet of flowers.
It's essential to differentiate between the adjectival and adverbial uses. For instance, 'a pretty dress' (adjective) vs. 'pretty tired' (adverb).
as an adverb, 'pretty' is used informally to emphasize or modify the degree of an adjective or another adverb, similar to 'quite' or 'rather.'
The movie was pretty good.
She runs pretty fast for her age.
I'm pretty sure he'll come to the party.
'Pretty' as an adverb can be considered colloquial and might not be suitable for very formal writing or speech. Some people might find the adverbial use of 'pretty' to be vague, as it doesn't specify the exact degree of the adjective it's modifying.