Folk from Gaelic land (4)
I believe the answer is:
clan
'folk' is the definition.
(thesaurus)
'from gaelic land' is the wordplay.
'from' indicates the answer is hidden within the clue.
'CLAN' is hidden in the letters of 'gaelic land'.
(Other definitions for clan that I've seen before include "Scottish family grouping" , "Group with common ancestor, like the Campbells" , "One from Benghazi" , "Group of families with common ancestor" , "Scots family grouping" .)