Desire to move on, abandoning bold, malicious poetry (5,4)
I believe the answer is:
itchy feet
'desire to move on' is the definition.
'abandoning bold malicious poetry' is the wordplay.
'abandoning' indicates named letters should be taken away.
'bold' becomes 'b' (abbreviation).
'malicious' becomes 'bitchy' (similar in meaning).
'poetry' becomes 'feet' (poetic structures are made up of metric feet).
'bitchy' with 'b' taken away is 'itchy'.
'itchy'+'feet'='ITCHY FEET'
(Other definitions for itchy feet that I've seen before include "Restlessness, a desire to travel - or scratch?" , "reason for leaving?" , "They show a strong urge to travel" , "Have . . . . . . . . . with restless desire to travel" , "Those with these have a strong impulse to travel" .)