Deep regard, it's said (3)
I believe the answer is:
sea
'deep' is the definition.
(thesaurus)
'regard it's said' is the wordplay.
'regard' becomes 'see' ('see' can be a synonym of 'regard').
'it's said' shows a homophone (sound like).
'see' is a homophone of 'SEA'.
(Other definitions for sea that I've seen before include "eg Dead, Red" , "7 [ship] s on this" , "Large expanse of water" , "Part of ocean" , "Cod's home?" .)