Specified an intention on the wrong date (10)
I believe the answer is:
designated
'specified' is the definition.
('designate' can be a synonym of 'specify')
'an intention on the wrong date' is the wordplay.
'an intention' becomes 'design' (I've seen this in another clue).
'on' means one lot of letters goes inside another.
'the wrong' indicates an anagram.
'date' anagrammed gives 'ated'.
'design' inserted inside 'ated' is 'DESIGNATED'.
(Other definitions for designated that I've seen before include "Given a specific status" , "Nominated" .)