Who could be undone by introduction of his E-fit? (5)
I believe the answer is:
thief
'who could be undone by introduction of his e-fit?' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'undone by introduction of his e-fit?' is the wordplay.
'undone by' is an anagram indicator (the original order of letters must be undone).
'introduction of' says to take the initial letters.
The initial letter of 'his' is 'h'.
'h'+'e'+'fit'='hefit'
'hefit' with letters rearranged gives 'THIEF'.
Can you help me to learn more?
(Other definitions for thief that I've seen before include "One with taking ways" , "Criminal" , "Raffles, say" , "Larcenist" , "One's inclined to take" .)