What does the cryptic crossword clue "Foul dictator has lost out (5)" mean?

The definition is "Foul". The wordplay uses a deletion. STAIN (deletion) = STAIN; definition: "Foul" The answer is STAIN.

Foul dictator has lost out (5)

Guardian Cryptic #28959 | 26 Across | 2023-01-05 flower