Head of department with silver getting German weapon (6)
I believe the answer is:
dagger
'weapon' is the definition.
(dagger is a kind of weapon)
'head of department with silver getting german' is the wordplay.
'head of' indicates taking the first letters.
'with' is a charade indicator (letters next to each other).
'silver' becomes 'Ag' (Ag is the chemical symbol for silver).
'getting' is a charade indicator (letters next to each other).
'german' becomes 'ger' (abbreviation).
The initial letter of 'department' is 'd'.
'd'+'ag'+'ger'='DAGGER'
(Other definitions for dagger that I've seen before include "that has an incisive point" , "Stabbing weapon" , "The weapon Macbeth thought he saw" , "A weapon; a reference mark" , "Hand weapon" .)