Entire CID's mobilised lacking diplomacy (10)
I believe the answer is:
indiscreet
'lacking diplomacy' is the definition.
(discretion can mean tact or diplomacy)
'entire cid's mobilised' is the wordplay.
'mobilised' indicates anagramming the letters (I've seen this in other clues).
'entire'+'cids'='entirecids'
'entirecids' is an anagram of 'INDISCREET'.
(Other definitions for indiscreet that I've seen before include "Too ready to reveal secret things" , "Ill-judged" , "Tactless" , "Imprudent -- 10 across (anag)" , "shameless" .)