Feeling one put into words (9)
I believe the answer is:
sentience
'feeling one put into words' is the definition.
I can't judge whether this defines the answer.
'feeling one put into words' is the wordplay.
'feeling one' becomes 'i' (Roman numeral. I am not sure about the 'feeling' bit.).
'put into' means one lot of letters goes inside another.
'words' becomes 'sentence' (I've seen this before).
'i' inserted into 'sentence' is 'SENTIENCE'.
Can you help me to learn more?
(Other definitions for sentience that I've seen before include "Ability to feel or perceive" , "awareness" , "Ability to feel things" , "Consciousness -- ten nieces (anag)" , "Feeling" .)