Not an hour to be hopping on every second island (4)
I believe the answer is:
oahu
'every second island' is the definition.
'oahu' can be an answer for 'island' (island in Hawaii). I'm not certain of the 'every second' bit.
'not an hour to be hopping' is the wordplay.
'not' becomes 'o' (I've seen this in other clues).
'an' becomes 'a'.
'hour' becomes 'h' (abbreviation).
'to be hopping' becomes 'u' (I can't justify this - if you can you should give a lot more credence to this answer).
'o'+'a'+'h'+'u'='OAHU'
'on' is the link.
Can you help me to learn more?
(Other definitions for oahu that I've seen before include "Pacific island" , "popular Pacific location" , "Honolulu's island" , "Chief island of Hawaii" , "Hawaiian island" .)