Conservative setter taking in a clot (7)
I believe the answer is:
congeal
'clot' is the definition.
(I've seen this in another clue)
'conservative setter taking in a' is the wordplay.
'conservative' becomes 'con' (abbreviation for Conservative).
'setter' becomes 'gel' (something which sets).
'taking in' indicates putting letters inside.
'gel' enclosing 'a' is 'geal'.
'con'+'geal'='CONGEAL'
(Other definitions for congeal that I've seen before include "Solidify by cooling" , "Curdle" , "Become gelatinous" , "cake" , "Become solid" .)