Old boy in car nobbled hooded killer (5)
I believe the answer is:
cobra
'hooded killer' is the definition.
(I've seen this in another clue)
'old boy in car nobbled' is the wordplay.
I cannot quite understand how this works, but
'old' could be 'o' (common abbreviation eg in OE for Old English) and 'o' is located in the answer.
'boy' could be 'b' (abbreviation used in schools) and 'b' is found within the answer.
an anagram of 'car' is 'cra' which is located in the left over letters.
No letters remain.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for cobra that I've seen before include "one leading charmed life?" , "hamadryad" , "Poisoner" , "a king, for example" , "Something with a hood" .)