lie in wait vs ambush

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

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

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

Other synonyms of lie in wait include ambuscade, bushwhack, lurk, scupper, waylay.

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

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