Pick a fight with celebrity running around Thailand (5,2)
I believe the answer is:
start on
'pick a fight with' is the definition.
I can't judge whether this defines the answer.
'celebrity running around thailand' is the wordplay.
'celebrity' becomes 'star' (a star is a celebrity or famous person).
'running' becomes 'on' (eg when a machine is running it is on).
'around' is an insertion indicator.
'thailand' becomes 'T' (abbreviation on car registration plates).
'star'+'on'='staron'
'staron' going around 't' is 'START ON'.
Can you help me to learn more?
(Other definitions for start on that I've seen before include "Begin to deal with" , "Attack" .)