Be conspicuous in booth in the open (5,3)
I believe the answer is:
stand out
'be conspicuous' is the definition.
(I've seen this before)
'booth in the open' is the wordplay.
'booth' becomes 'stand'.
'in the open' becomes 'out' (I've seen this before).
'stand'+'out'='STAND OUT'
'in' is the link.
(Other definitions for stand out that I've seen before include "Catch the eye" , "Refuse to agree - project" , "Don't agree to - project" , "highlighted?" , "Be conspicuous, or persist in demand" .)