Hollow and irritated about Republican (6)
I believe the answer is:
grotto
'hollow' is the definition.
'irritated about republican' is the wordplay.
'irritated' becomes 'gotto' ('get to' can be a synonym of 'irritate').
'about' is an insertion indicator.
'republican' becomes 'r' (abbreviation).
'gotto' placed around 'r' is 'GROTTO'.
'and' is the link.
(Other definitions for grotto that I've seen before include "It's left on Dec 24 by Santa and his reindeer" , "Ornamental cave" , "fancy underground area" , "Type of cave, often with religious significance" , "Small cave as at Lourdes" .)