Ship lay at sea to receive chief's initial examination (8)
I believe the answer is:
physical
'examination' is the definition.
(kind of examination)
'ship lay at sea to receive chief's initial' is the wordplay.
'at sea' is an anagram indicator.
'to receive' indicates putting letters inside.
'initial' indicates taking the first letters.
The initial letter of 'chiefs' is 'c'.
'ship'+'lay'='shiplay'
'shiplay' anagrammed gives 'physial'.
'physial' enclosing 'c' is 'PHYSICAL'.
(Other definitions for physical that I've seen before include "of concrete structure" , "Involving matter, the body say" , "Bodily - material" , "Involving bodily contact" , "Medical check" .)