slip-joint pliers vs plyers

slip-joint pliers and plyers both are nouns.

Word	Noun	Adjective	Verb	Adverb
slip-joint pliers	Yes	No	No	No
plyers	Yes	No	No	No

As nouns, plyers is a hypernym of slip-joint pliers; that is, plyers is a word with a broader meaning than slip-joint pliers:

slip-joint pliers: pliers with a joint adjustable to two positions in order to increase the opening of the jaws
plyers: a gripping hand tool with two hinged arms and (usually) serrated jaws

Other hypernyms of slip-joint pliers include pair of pliers, pliers.

slip-joint pliers (noun)	plyers (noun)
pliers with a joint adjustable to two positions in order to increase the opening of the jaws	a gripping hand tool with two hinged arms and (usually) serrated jaws