Clever reply from Republican that is shown round office (7)
I believe the answer is:
riposte
'clever reply' is the definition.
'republican that is shown round office' is the wordplay.
'republican' becomes 'r' (abbreviation).
'that is' becomes 'ie' ('i.e.' can be a synonym of 'that is').
'shown round' indicates putting letters inside.
'office' becomes 'post' ('post' can be a synonym of 'office').
'ie' placed around 'post' is 'iposte'.
'r'+'iposte'='RIPOSTE'
'from' is the link.
(Other definitions for riposte that I've seen before include "Witty comeback" , "Poster I alter for repartee" , "Snappy comeback" , "Rejoin" , "Fencer's counterattack" .)