One gets on with it, picking up spear (7)
I believe the answer is:
assegai
'spear' is the definition.
(I've seen this before)
'one gets on with it picking up' is the wordplay.
'one' becomes 'i' (Roman numeral).
'gets on' becomes 'ages' ('age' can be a synonym of 'get on').
'with' is a charade indicator (letters next to each other).
'it' becomes 'sa' (old-fashioned abbreviation for sex appeal).
'picking up' is a reversal indicator.
'i'+'ages'+'sa'='iagessa'
'iagessa' reversed gives 'ASSEGAI'.
(Other definitions for assegai that I've seen before include "Ages as I threw the spear" , "Wooden spear of southern Africa" , "African weapon" , "A Zulu warrior's spear" , "Spear used in southern Africa" .)