Josh is boring jerk? Very sad (6)
I believe the answer is:
tragic
'very sad' is the definition.
(tragic can mean very sad or unfortunate)
'josh is boring jerk?' is the wordplay.
'josh' becomes 'rag' (both can mean to mock).
'is boring' means one lot of letters goes inside another (some letters must 'bore' a hole into other letters).
'jerk?' becomes 'tic' (jerking movement by the body).
'rag' placed inside 'tic' is 'TRAGIC'.
(Other definitions for tragic that I've seen before include "Extremely sad and distressing" , "Heart-rending" , "heartbreaking" , "Shocking" , "Involving grief of death or destruction" .)