Isolated foreign aid corps (8)
I believe the answer is:
sporadic
'isolated' is the definition.
(similar in meaning)
'foreign aid corps' is the wordplay.
'foreign' indicates an anagram (foreign order of the letters).
'aid'+'corps'='aidcorps'
'aidcorps' is an anagram of 'SPORADIC'.
(Other definitions for sporadic that I've seen before include "Occasional - intermittent" , "Random" , "Having separate patches" , "Isolated; intermittent" , "Scattered - irregular" .)