Computer peripheral with no second function (3)
I believe the answer is:
use
'function' is the definition.
(I know that function can be written as use)
'computer peripheral with no second' is the wordplay.
'computer peripheral' becomes 'mouse' (I've seen this in another clue).
'with no' indicates named letters should be taken away.
'second' becomes 'mo' (both are short periods of time).
'mouse' with 'mo' taken out is 'USE'.
(Other definitions for use that I've seen before include "Employ or exploit" , "Exploit unfairly" , "Resort to - operation" , "Operate" , "Exploit; custom" .)