Illness making one conk out when traversing oceans? (7)
I believe the answer is:
disease
'illness' is the definition.
(disease is a kind of health problem)
'conk out when traversing oceans?' is the wordplay.
'conk out' becomes 'die' (synonyms).
'when traversing' is an insertion indicator (traverse can mean to go around).
'oceans?' becomes 'seas' ('sea' can be a synonym of 'ocean').
'die' placed around 'seas' is 'DISEASE'.
'making one' is the link.
(Other definitions for disease that I've seen before include "Impairment of health" , "affection" , "Ailment, malady" , "scrapie for example" , "Seaside (anag) -- ailment" .)