I am old model, overwhelmed by some strong hostility (9)
I believe the answer is:
animosity
'strong hostility' is the definition.
(I've seen this before)
'i am old model overwhelmed by some' is the wordplay.
'i am old' becomes 'imo' (I can't explain this - if you can you should believe this answer much more).
'model' becomes 'sit' ('sit' can be a synonym of 'model').
'overwhelmed by' means one lot of letters goes inside another (I've seen this in other clues).
'some' becomes 'any' ('any' can be similar in meaning to 'some').
'imo'+'sit'='imosit'
'imosit' going inside 'any' is 'ANIMOSITY'.
Can you help me to learn more?
(Other definitions for animosity that I've seen before include "Is no amity in rancour" , "Strong hostility" , "Ill-will" , "Maoist yin generates spirit of hostility" , "Hostility concealed by sanity - moi?" .)