Artist, extremely reclusive and seldom seen (4)
I believe the answer is:
rare
'seldom seen' is the definition.
(something seldom seen is seen rarely)
'artist extremely reclusive' is the wordplay.
'artist' becomes 'RA' (Royal Academician, member of Royal Academy of Arts).
'extremely' says to hollow out the word (remove centre letters) (only the extremes of the word are used).
'reclusive' with its middle taken out is 're'.
'ra'+'re'='RARE'
'and' is the link.
(Other definitions for rare that I've seen before include "Not common" , "Not easily come by like undercooked meat" , "Special" , "of low density" , "little done?" .)