Please get out when dormant (6)
I believe the answer is:
asleep
'dormant' is the definition.
(similar in meaning)
'please get out' is the wordplay.
'get out' is an anagram indicator (the letters get out of order).
'please' is an anagram of 'ASLEEP'.
'when' is the link.
(Other definitions for asleep that I've seen before include "Snoozing" , "out like a light?" , "Out for the count" , "In slumber" , "Dormant, inactive" .)