Top bets may be lost (4)
I believe the answer is:
best
'top' is the definition.
(associated in meaning)
'bets may be lost' is the wordplay.
'bets' can be anagrammed to 'BEST'.
However, I'm unsure how the anagram is indicated.
Can you help me to learn more?
(Other definitions for best that I've seen before include "former football star" , "Limit of one's ability" , "To the highest standard" , "Of the highest quality" , "Most outstanding" .)