Can you use a clue that contains a word on the board within it in an unrelated way in Codenames?
Yes, you can.

While certain questions like this will be up to each play group to decide; this one is actually directly addressed in the rules.

At the bottom of page 6:


  England and island were originally compound words, but in this century, island is a valid clue for
  ENGLAND. Even land is a valid clue for ENGLAND. And anybody who says you can't say sparrow when
  ROW is on the table is just trying to cause trouble.