leave vs step out

leave is a noun but step out is not a noun.

Word	Noun	Adjective	Verb	Adverb
leave	Yes	No	Yes	No
step out	No	No	Yes	No

As verbs, step out is a hyponym of leave; that is, step out is a word with a more specific, narrower meaning than leave:

Other hyponyms of leave include depart, go, go away, pop out, file out, get off, hop out, fall out, get off, eject, undock, log off, log out.

leave (noun)	step out (noun)
the act of departing politely
permission to do something
the period of time during which you are absent from work or duty

leave (verb)	step out (verb)
leave unchanged or undisturbed or refrain from taking	go outside a room or building for a short period of time
be survived by after one's death
leave behind unintentionally
go and leave behind, either intentionally or by neglect or forgetfulness
move out of or depart from
go away from a place
leave or give by will after one's death
transmit (knowledge or skills)
put into the care or protection of someone
remove oneself from an association with or participation in
produce as a result or residue
make a possibility or provide opportunity for; permit to be attainable or cause to remain
act or be so as to become in a specified state
have left or have as a remainder