What does the cryptic crossword clue "Revolting friend's make-up (4)" mean?

The definition is "make-up". The wordplay uses a reversal. reverse of PALS = SLAP; definition: "make-up" The answer is SLAP.

Revolting friend's make-up (4)

Guardian Cryptic #29234 | 9 Across | 2023-11-22 flower