How bowler may be lost without thinking? (2,3,4,2,1,3)
I believe the answer is:
at the drop of a hat
'without thinking?' is the definition.
(at the drop of a hat means without preparation)
'how bowler may be lost' is the wordplay.
I cannot quite see how this works, but
'bowler' could be 'hat' (bowler is a type of hat) and 'hat' is found within the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for at the drop of a hat that I've seen before include "Immediately" , "suddenly?" , "in no time at all" , "without good reason?" , "Derby's relegation signalled thus" .)