Miss a burst boil because of a squint (10)
I believe the answer is:
strabismus
'a squint' is the definition.
(I know that squint can be written as strabismus)
'miss a burst boil' is the wordplay.
'boil' indicates an anagram (I've seen 'boiled' mean this (letters cooked or boiled into a new form)).
'miss'+'a'+'burst'='missaburst'
'missaburst' is an anagram of 'STRABISMUS'.
'because of' is the link.
(Other definitions for strabismus that I've seen before include "complaint" , "Squint condition; Doctor of Utrecht (Beachcomber)" .)