A male cat gets something tiny (4)
I believe the answer is:
atom
'something tiny' is the definition.
(I know that atoms are tiny)
'a male cat' is the wordplay.
'male cat' becomes 'tom' (a male cat is called a tom).
'a'+'tom'='ATOM'
'gets' acts as a link.
(Other definitions for atom that I've seen before include "Particle; molecule" , "A mighty particle, makes huge explosion" , "A tiny powerful particle" , "type of bomb" , "Very small object or amount" .)