Fingerprint or footprint, perhaps (4)
I believe the answer is:
clue
(Other definitions for clue that I've seen before include "Hint; piece of evidence" , "What's this" , "Hint to help the solver" , "Crossword aid" , "Hint, tip" .)
I believe the answer is:
clue
(Other definitions for clue that I've seen before include "Hint; piece of evidence" , "What's this" , "Hint to help the solver" , "Crossword aid" , "Hint, tip" .)