Dad takes shelter, that's clear (6)
I believe the answer is:
patent
'clear' is the definition.
(synonyms)
'dad takes shelter' is the wordplay.
'dad' becomes 'pa' (both can mean one's father).
'takes' says to put letters next to each other.
'shelter' becomes 'tent' (canvas shelter).
'pa'+'tent'='PATENT'
'that's' is the link.
(Other definitions for patent that I've seen before include "The right to an invention is clear" , "Blatant" , "unmistakeable" , "Open the right to an invention" , "glaring" .)