slide vs slide down

slide is a noun but slide down is not a noun.

Word	Noun	Adjective	Verb	Adverb
slide	Yes	No	Yes	No
slide down	No	No	Yes	No

slide (noun)	slide down (noun)
the act of moving smoothly along a surface while remaining in contact with it
sloping channel through which things can descend
a transparency mounted in a frame; viewed with a slide projector
a small flat rectangular piece of glass on which specimens can be mounted for microscopic study
plaything consisting of a sloping chute down which children can slide
(music) rapid sliding up or down the musical scale
(geology) the descent of a large mass of earth or rocks or snow etc.

slide (verb)	slide down (verb)
to pass or move unobtrusively or smoothly	fall or sink heavily
move obliquely or sideways, usually in an uncontrolled manner
move smoothly along a surface