Impatience in chess? It’s disastrous (9)
I believe the answer is:
itchiness
'impatience' is the definition.
(as in itching to do something)
'in chess? it's disastrous' is the wordplay.
'disastrous' is an anagram indicator.
'in'+'chess'+'it'='inchessit'
'inchessit' is an anagram of 'ITCHINESS'.
(Other definitions for itchiness that I've seen before include "Feeling of irritation" , "It produces the desire to scratch" , "some experience after seven years in union?" , "tingling" , "Skin irritation" .)