ambush vs lie in wait

ambush is a noun but lie in wait is not a noun.

Word	Noun	Adjective	Verb	Adverb
ambush	Yes	No	Yes	No
lie in wait	No	No	Yes	No

As verbs, ambush and lie in wait are synonyms defined as:

Other synonyms of ambush include ambuscade, bushwhack, lurk, scupper, waylay.

ambush (noun)	lie in wait (noun)
the act of concealing yourself and lying in wait to attack by surprise

ambush (verb)	lie in wait (verb)
wait in hiding to attack	wait in hiding to attack
hunt (quarry) by stalking and ambushing