Horse, one sporting queer ears more inclined to droop (7)

'more inclined to droop' is the definition.
(more likely to sag or droop)

'horse one sporting queer ears' is the wordplay.
'horse' becomes 'gg' (geegee or GG is a childish term for a horse).
'one' becomes 'i' (Roman numeral).
'sporting' is an insertion indicator (inserted letters wear or 'sport' others).
'queer' is an anagram indicator.
'gg'+'i'='ggi'
'ears' with letters rearranged gives 'saer'.
'ggi' inserted inside 'saer' is 'SAGGIER'.