A snip to go without underwear in casualty (2-7)
I believe the answer is:
no-brainer
'a snip to' is the definition.
I don't know anything about this answer so I can't tell whether this works.
'without underwear in casualty' is the wordplay.
I cannot quite see how this works, but
'without' could be 'no' and 'no' is found within the answer.
'underwear' could be 'bra' (bra is a type of undergarment) and 'bra' is found within the answer.
'in' is found in the answer.
The remaining letters 'er' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
'go' acts as a link.
Can you help me to learn more?
(Other definitions for no-brainer that I've seen before include "An easy decision" , "Something requiring little thought" , "Something requiring no mental thought" , "Obvious choice" , "Trivial problem" .)