Dry and tense religious group (4)
I believe the answer is:
sect
'religious group' is the definition.
(I've seen this before)
'dry and tense' is the wordplay.
'dry' becomes 'sec' ('sec' can be similar in meaning to 'dry').
'and' is a charade indicator (letters next to each other).
'tense' becomes 't' (abbreviation used in many dictionaries).
'sec'+'t'='SECT'
(Other definitions for sect that I've seen before include "Subdivision of a religion" , "Subdivision of a larger religious group" , "Religious splinter group" , "Group of people with unusual religious beliefs" , "Small group with own religious beliefs" .)