step vs step out

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

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

step (noun)	step out (noun)
the act of changing location by raising the foot and setting it down
any maneuver made as part of progress toward a goal
a sequence of foot movements that make up a particular dance
support consisting of a place to rest the foot while ascending or descending a stairway
a solid block joined to the beams in which the heel of a ship's mast or capstan is fixed
a musical interval of two semitones
a mark of a foot or shoe on a surface
the sound of a step of someone walking
the distance covered by a step
a short distance
relative position in a graded series

step (verb)	step out (verb)
measure (distances) by pacing	go outside a room or building for a short period of time
move or proceed as if by steps into a new situation
place (a ship's mast) in its step
shift or move by taking a step
put down or press the foot, place the foot
walk a short distance to a specified place or in a specified manner
move with one's feet in a specific manner
furnish with steps
treat badly
cause (a computer) to execute a single command