Pretty vs pretty

[Jgap]

How can I explain to my students the definitionbetween pretty as "pretty girl" against "pretty good".

[David L.]

'pretty girl'- pretty is being used as an adjective, indicating being
attractive in a delicate way.

However, it can also be used informally and ironically in everyday speech to express annoyance or disgust : "So much for loyalty between friends. It is a pretty state of affairs when your own best friend turns you in to the Gestapo."
It can also be used informally to mean, 'to a moderately high degree' : he looked pretty fit for his age.
Does that help?

[Jgap]

Yes, it did help me, specially on the ironic usage of pretty.
Your help was pretty good!
Thanks,
Jgap