Grasp that husband gets aged (4)
I believe the answer is:
hold
'grasp' is the definition.
(I know that grasp can be written as hold)
'husband gets aged' is the wordplay.
'husband' becomes 'h' (abbreviation).
'gets' says to put letters next to each other.
'aged' becomes 'old' (similar in meaning).
'h'+'old'='HOLD'
'that' acts as a link.
(Other definitions for hold that I've seen before include "Nelson?" , "Have or possess" , "Maintain" , "Keep in one's grasp" , "Cargo area of ship" .)