put on vs slap on

put on is an adjective but slap on is not an adjective.

Word	Noun	Adjective	Verb	Adverb
put on	No	Yes	Yes	No
slap on	No	No	Yes	No

As verbs, slap on is a hyponym of put on; that is, slap on is a word with a more specific, narrower meaning than put on:

Other hyponyms of put on include dab, swab, swob, daub, gum, dress, cream, cold-cream, putty, sponge on, clap on, slam on.

put on (adjective)	slap on (adjective)
adopted in order to deceive

put on (verb)	slap on (verb)
put clothing on one's body	apply carelessly
increase (one's body weight)
add to something existing
add to the odometer
fool or hoax
coat, cover or smear a surface with
prepare and supply with the necessary equipment for execution or performance
carry out (performances)
put on the stove or ready for cooking