Department H shows intensity (5)
I believe the answer is:
depth
'intensity' is the definition.
(I've seen this before)
'department h' is the wordplay.
'department' becomes 'dept'.
'dept'+'h'='DEPTH'
'shows' acts as a link.
(Other definitions for depth that I've seen before include "Downward extent" , "Military life; vulgarly artificial" , "Intensity (of emotion)" , "Profoundness" , "Distance from the surface to the bottom" .)