Barely beat, with "by" (3)
I believe the answer is:
eke
'barely beat with by' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for eke that I've seen before include "Make a laborious living" , "Stretch (out); in addition (archaic)" , "To -- out is to add to" , "long ago" , "Supplement" .)