Split with one hundred remaining (5)
I believe the answer is:
cleft
'split' is the definition.
(cleft can mean split or cloven)
'with one hundred remaining' is the wordplay.
'with' means one lot of letters go next to another.
'one hundred' becomes 'c' (Roman numeral).
'remaining' becomes 'left' (synonyms).
'c'+'left' is 'CLEFT'.
(Other definitions for cleft that I've seen before include "Split or indentation" , "Split, divided" , "division" , "split along natural lines" , "Fissure in rock" .)