Crazily firing without notice -- that's demeaning (5,3)
I believe the answer is:
Here is my best explanation:
'demeaning' is the definition.
(I've seen this before)
'crazily firing without notice' is the subsidiary indication.
'crazily' indicates an anagram.
'without' indicates putting letters inside.
'notice' becomes 'ad'.
'firing' is an anagram of 'infrig'.
'infrig' going around 'ad' is 'infradig'.
'that's' is the link.
(Other definitions for infra dig that I've seen before include "Such as one would not stoop to", "Beneath one", "Unbecoming, if daring criminal", "Beneath oneself (from Latin)", "Rigid fan may be lacking in dignity", "Demeaning (Lat. abbr.)" and "Demeaning (Latin)".)