くっつける
くっつける · kuttsukeru · JLPT N2 · verb-ichidan
to attach
🧲 Decomposes as くっつく (to stick) + ける (causative): make it stick = attach
くっつく is the intransitive 'to stick to'. Adding the causative ending ける makes it transitive, so the verb means to make one thing stick to another.