Tending to scare off star Liam (8)
I believe the answer is:
alarmist
'tending to scare' is the definition.
(creating alarm)
'off star liam' is the wordplay.
'off' indicates anagramming the letters.
'star'+'liam'='starliam'
'starliam' with letters rearranged gives 'ALARMIST'.
(Other definitions for alarmist that I've seen before include "One who worries others needlessly" , "prophet of doom" , "Person exaggerating danger" , "Like panicking passenger" , "One who cries wolf" .)