Sign with appeal to people (4)
I believe the answer is:
omen
'sign' is the definition.
(I've seen this before)
'with appeal to people' is the wordplay.
'with' means one lot of letters go next to another.
'appeal' becomes 'o'.
'to people' becomes 'men' (man is a kind of person).
'o' next to 'men' is 'OMEN'.
(Other definitions for omen that I've seen before include "Prognostication" , "Sign of likely future event" , "Harbinger, augury" , "Warning - sign" , "writing on the wall" .)