SOLUTION: The pictures correspond to the following letters:
Cat=C, Cake=A, Knot=T, Ant=N, Nut=U, Kite=E, Coat=O, Key=K, Eye=Y, and the ?=I.  The five letter word is thus UNITE, and we know that goes with the question mark because the question mark was the removed heart which always represents that word, "plus it's easy to spell, but hard to draw"


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