Taking office is concise as can be (9)
I believe the answer is:
accession
'taking office' is the definition.
(I've seen this before)
'concise as can be' is the wordplay.
'can be' indicates an anagram.
'concise'+'as'='conciseas'
'conciseas' is an anagram of 'ACCESSION'.
'is' acts as a link.
(Other definitions for accession that I've seen before include "New item added to a library or museum" , "Act of taking up office" .)