... something inherited in Guernsey regularly (4)
I believe the answer is:
gene
'something inherited' is the definition.
(I've seen this in another clue)
'guernsey regularly' is the wordplay.
'regularly' means one should take alternating letters (regularly take one letter, leave next etc.).
The alternating letters of 'guernsey' are 'GENE'.
'in' acts as a link.
(Other definitions for gene that I've seen before include "Part of DNA" , "Embarrassment" , "A segment of DNA" , "Something got from parent < for boy" , "-- Pitney, singer" .)