Caught speeding? That's devastating! (8)
I believe the answer is:
crushing
'devastating' is the definition.
(both can mean causing great distress)
'caught speeding?' is the wordplay.
'caught' becomes 'c' (cricket abbreviation).
'speeding?' becomes 'rushing' ('rush' can be a synonym of 'speed').
'c'+'rushing'='CRUSHING'
'that's' acts as a link.
(Other definitions for crushing that I've seen before include "Squeezing together" , "Violently subduing (opposition)" .)