Award, securing one first in chemistry examination (7)
I believe the answer is:
medical
'examination' is the definition.
(medical examination is a kind of examination)
'award securing one first in chemistry' is the wordplay.
'award' becomes 'medal' (medal is a kind of award**).
'securing' is an insertion indicator.
'one' becomes 'i' (Roman numeral).
'first in' suggests taking the first letters.
The initial letter of 'chemistry' is 'c'.
'i'+'c'='ic'
'medal' going around 'ic' is 'MEDICAL'.
(Other definitions for medical that I've seen before include "Check-up - declaim (anag)" , "Examination of physical health" , "Of the healing sciences" , "Test for health" , "Of the science dealing with treatment of disease" .)