Living in water with a pimple in command (7)
I believe the answer is:
aquatic
'living in water' is the definition.
(I've seen this in another clue)
'with a pimple in command' is the wordplay.
'with' means one lot of letters go next to another.
'pimple' becomes 'quat' (I can't explain this - if you can you should believe this answer much more).
'in command' becomes 'ic' (military abbreviation).
'a'+'quat' is 'aquat'.
'aquat'+'ic'='AQUATIC'
Can you help me to learn more?
(Other definitions for aquatic that I've seen before include "Of the water, its animals, its sports" , "such as teal?" , "20 [TERRAPIN] is" , "Watery (environment)" , "Living in/near water" .)