If something sticky wears something else on it, it will stick together because there's adhesion between them.

粘着 refers to the adhesive properties of a material, especially in compound words like 粘着テープ (adhesive tape). On its own, it often describes the behavior of people who can't let go of a particular issue and keep on about it in unwanted ways.

This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.