Nervous, stand holding the poles (5)
I believe the answer is:
tense
'nervous' is the definition.
(similar in meaning)
'stand holding the poles' is the wordplay.
'stand' becomes 'tee' (I've seen this before).
'holding' indicates putting letters inside.
'the poles' becomes 'NS' (North and South poles).
'tee' enclosing 'ns' is 'TENSE'.
(Other definitions for tense that I've seen before include "Nerve-racking" , "under pressure" , "Anxious - future, perhaps?" , "in the past, perhaps" , "Anxious, high-strung" .)