Half-heartedly excite popular old Asian islander (8)
I believe the answer is:
filipino
'islander' is the definition.
(I've seen this before)
'half-heartedly excite popular old asian' is the wordplay.
I cannot really see how this works, but
'popular' could be 'in' (something that's 'in' is fashionable) and 'in' is present in the answer.
'old' could be 'o' (abbreviation as in OT - Old Testament) and 'o' is found in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for filipino that I've seen before include "Nationality of citizen of Manila" , "One coming from Manila?" , "Nationality of native of Manila" , "Asian" , "Person from the Philippines" .)