Here's the rule for reference:
You can't say part of a compound word on the table. Until HORSESHOE is covered up, you can't say horse, shoe, unhorsed, or snowshoe.
Clearly you can't say any of those clues to get your team to guess HORSESHOE, but does this rule still apply if you're referring to other cards (i.e. HORSESHOE is not one of your cards)?
This just happened in a recent game:
The Spymaster gave the clue "Man:2" which prompted some arguing. If the rule still applies in this case, that means this would never be a legal clue in the game since the assassin would never be covered up, correct?