That lady will shortly launch an attack (5)
I believe the answer is:
shell
'an attack' is the definition.
(I know that shell is a type of bomb)
'that lady will shortly launch' is the wordplay.
'that lady' becomes 'shel' ().
'will' says to put letters next to each other (I've seen this in other clues).
'shortly' indicates taking the first letters.
The initial letter of 'launch' is 'l'.
'shel'+'l'='SHELL'
(Other definitions for shell that I've seen before include "Carapace; bombard" , "magazine article" , "Walls of gutted building" , "Hard protective case" , "attack with bombs" .)