Lent ear foolishly, without beginning or end (7)
I believe the answer is:
eternal
'without beginning or end' is the definition.
(I've seen this before)
'lent ear foolishly' is the wordplay.
'foolishly' indicates an anagram.
'lent'+'ear'='lentear'
'lentear' anagrammed gives 'ETERNAL'.
(Other definitions for eternal that I've seen before include "like Rome?" , "Seemingly without end" , "Forever, never-ending" , "Constant" , "Timeless" .)