In other words, needs to tear round to validate (7)
I believe the answer is:
endorse
'validate' is the definition.
(thesaurus)
'in other words needs to tear round' is the wordplay.
'in other words' becomes 'or' (I've seen this in other clues).
'to tear' indicates an anagram.
'round' is an insertion indicator.
'needs' is an anagram of 'endse'.
'or' put within 'endse' is 'ENDORSE'.
'to' is the link.
(Other definitions for endorse that I've seen before include "Corroborate" , "Champion" , "Approve or underwrite" , "Give one's sanction to" , "Put one's name to, approve" .)