Blundering in chess? It's an irritating feeling! (9)
I believe the answer is:
itchiness
'irritating feeling' is the definition.
'itchiness' can be an answer for 'feeling' (I have seen 'Feeling of irritation' mean 'itchiness' so perhaps 'feeling' could also mean 'itchiness'). I am not certain of the 'irritating' bit.
'blundering in chess? it's an' is the wordplay.
'blundering' is an anagram indicator (I've seen 'blunder' mean this).
'it' becomes ''t' (abbreviation. e.g. in 'tis).
'an' becomes 'i' (Roman numeral for one).
'in'+'chess'+'t'+'i'='inchessti'
'inchessti' with letters rearranged gives 'ITCHINESS'.
Can you help me to learn more?
(Other definitions for itchiness that I've seen before include "irritating" , "It produces the desire to scratch" , "some experience after seven years in union?" , "Skin irritation" , "tingling" .)