Tail dig agitated type of clock (7)
I believe the answer is:
digital
'type of clock' is the definition.
(I've seen this before)
'tail dig agitated' is the wordplay.
'agitated' indicates an anagram.
'tail'+'dig'='taildig'
'taildig' with letters rearranged gives 'DIGITAL'.
(Other definitions for digital that I've seen before include "Displaying in numbers like some watches" , "Using fingers" , "Of data expressed as a series of 0 and 1" , "Key" , "Like modern cameras" .)