British holidaymaker initially admits Los Angeles is dull (4)
I believe the answer is:
blah
'dull' is the definition.
(thesaurus)
'british holidaymaker initially admits los angeles' is the wordplay.
'initially' says to take the initial letters.
'admits' is an insertion indicator.
'los angeles' becomes 'la'.
The first letters of 'british holidaymaker' is 'bh'.
'bh' placed around 'la' is 'BLAH'.
'is' acts as a link.
(Other definitions for blah that I've seen before include "Dull" , "Stupid 20" , "Pretentious nonsense" , "Claptrap" , "Bombast" .)