Speculate about a copper's course
I believe the answer is:
beat
'copper's course' is the definition.
'beat' can be an answer for 'course' (thesaurus). I'm unsure of the 'copper's' bit.
'speculate about a' is the wordplay.
'speculate' becomes 'bet' (to bet is to gamble or speculate).
'about' indicates putting letters inside.
'bet' enclosing 'a' is 'BEAT'.
Can you help me to learn more?
(Other definitions for beat that I've seen before include "Policeman's route; strike" , "Pound - defeat" , "Thrash with rhythm?" , "Thrash, punish physically" , "assigned patrol" .)