Eerie, lunar, they recollected (9)
I believe the answer is:
unearthly
'eerie' is the definition.
(thesaurus)
'lunar they recollected' is the wordplay.
'recollected' indicates an anagram.
'lunar'+'they'='lunarthey'
'lunarthey' with letters rearranged gives 'UNEARTHLY'.
(Other definitions for unearthly that I've seen before include "Mysterious and disturbing" , "Not of this world, supernatural" , "could be weird" , "Sunny" , "So unpleasantly early an hour" .)