Cannot possibly accommodate a child - not I (9)
I believe the answer is:
consonant
'i' is the definition.
Both the answer and definition are adjectives. Maybe there's an association between them I don't understand?
'cannot possibly accommodate a child' is the wordplay.
'possibly' indicates anagramming the letters.
'accommodate' indicates putting letters inside.
'a child' becomes 'son' (male child).
'cannot' is an anagram of 'conant'.
'conant' going around 'son' is 'CONSONANT'.
'not' acts as a link.
Can you help me to learn more?
(Other definitions for consonant that I've seen before include "Something like G, B and D" , "not I, nor you, one hears" , "B, C, D or F, perhaps?" , "Only one of Ouida's characters is" , "Letter; harmonious chord" .)