Lift up old key (5)
I believe the answer is:
exalt
'lift up' is the definition.
(I know that exalt is a kind of lift up)
'old key' is the wordplay.
'old' becomes 'ex' (prefix meaning former or onetime).
'key' becomes 'alt' (the Alt keyboard button).
'ex'+'alt'='EXALT'
(Other definitions for exalt that I've seen before include "Raise in rank, character, or status" , "Praise, glorify or honor" , "Elevate" , "Praise - latex (anag)" , "Honour - raise up" .)