lechery vs sexual activity

lechery and sexual activity both are nouns.

Word	Noun	Adjective	Verb	Adverb
lechery	Yes	No	No	No
sexual activity	Yes	No	No	No

As nouns, sexual activity is a hypernym of lechery; that is, sexual activity is a word with a broader meaning than lechery:

Other hypernyms of lechery include sex, sex activity, sexual practice.

lechery (noun)	sexual activity (noun)
unrestrained indulgence in sexual activity	activities associated with sexual intercourse