Cautious of administering a drug as a boy (7)
I believe the answer is:
guarded
'cautious' is the definition.
('guarded' can be similar in meaning to 'cautious')
'administering a drug as a boy' is the wordplay.
I cannot really understand how this works, but
'a' is present in the answer.
an anagram of 'drug' is 'gurd' which is within the remaining letters.
'boy' could be 'ed' and 'ed' is found in the answer.
No letters remain.
This explanation may well be incorrect...
'of' acts as a link.
Can you help me to learn more?
(Other definitions for guarded that I've seen before include "Reticent" , "Cagey or protected" , "Cautious; watched over" , "Kept watch over" , "with escort" .)