Keep time or we go wrong (5)
I believe the answer is:
tower
'keep' is the definition.
(I've seen this before)
'time or we go wrong' is the wordplay.
'time' becomes 't' (abbreviation).
'go wrong' is an anagram indicator.
'or'+'we'='orwe'
'orwe' anagrammed gives 'ower'.
't'+'ower'='TOWER'
(Other definitions for tower that I've seen before include "Tall building - loom (over)" , "See 6 Down" , "Tall structure" , "Turret" , "Wrote (anag.)" .)