Not as much between terminus and Cape Infinity? (11)
I believe the answer is:
endlessness
'infinity?' is the definition.
(thesaurus)
'not as much between terminus and cape' is the wordplay.
'not as much' becomes 'less' (similar in meaning).
'between' indicates putting letters inside.
'terminus' becomes 'end' (eg the end of a train line is its terminus).
'and' means one lot of letters go next to another.
'cape' becomes 'ness' (synonyms).
'end'+'ness'='endness'
'less' inserted within 'endness' is 'ENDLESSNESS'.
(Other definitions for endlessness that I've seen before include "Interminable quality" , "Interminability" , "No conclusion!" .)