No expert bet - lots of people going short (6)
I believe the answer is:
layman
'no expert' is the definition.
(I've seen this before)
'bet lots of people going short' is the wordplay.
'bet' becomes 'lay' (I've seen this in another clue).
'lots of people' becomes 'many' (many people).
'going short' means to remove the last letter.
'many' with its final letter removed is 'man'.
'lay'+'man'='LAYMAN'
(Other definitions for layman that I've seen before include "One without professional knowledge" , "He's not clergy or military" , "Person without specialised knowledge of subject" , "He's not ordained or professional" , "member of the congregation" .)