Said to be careful, it's booby-trapped (5)
I believe the answer is:
mined
'booby-trapped' is the definition.
(I've seen this in another clue)
'said to be careful it's' is the wordplay.
I cannot quite see how this works, but
'it' could be 'e' ('e' can mean 'electronic' which is similar to 'IT') and 'e' is found within the answer.
The remaining letters 'mind' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for mined that I've seen before include "laid eggs" , "proceeded secretly" , "Sought diamonds?" , "Placed charges" , "Quarried" .)