Barely beats, with "by" (4)
I believe the answer is:
ekes
'barely beats with by' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for ekes that I've seen before include "Lengthens (out)" , "Makes supplies last longer" , "...out a living, barely makes do" , "- - out: stretches" , "Rab C's extras" .)