Carrying out a limpet mine -- not to be disturbed! (14)
I believe the answer is:
implementation
'carrying out' is the definition.
('implementation' can be a synonym of 'carrying out')
'a limpet mine not to be disturbed' is the wordplay.
'to be disturbed' is an anagram indicator.
'a'+'limpet'+'mine'+'not'='alimpetminenot'
'alimpetminenot' is an anagram of 'IMPLEMENTATION'.
(Other definitions for implementation that I've seen before include "Putting in force" , "Carrying-out, fulfilment" , "Process of putting into effect" .)