Practice was gripping - it's often boring (5,3)
I believe the answer is:
drill bit
'often boring' is the definition.
Although both the answer and definition are singular nouns, I can't see how one could define the other.
'practice was gripping' is the wordplay.
'practice' becomes 'drill' (synonyms).
'was gripping' becomes 'bit' (bite can mean to grip).
'drill'+'bit'='DRILL BIT'
'it's' is the link.
Can you help me to learn more?
(Other definitions for drill bit that I've seen before include "Borer" , "tool" , "that bores" , "it can be boring" .)