Keep tearing endlessly around (6)
I believe the answer is:
retain
'keep' is the definition.
(retaining is a kind of keeping)
'tearing endlessly around' is the wordplay.
'endlessly' means to remove the last letter.
'around' is an anagram indicator.
'tearing' with its last letter taken off is 'tearin'.
'tearin' is an anagram of 'RETAIN'.
(Other definitions for retain that I've seen before include "Not relinquish" , "Hold onto" , "Keep in Tirane" , "Hold in position" , "Keep, hold on to something" .)