Like a broader smile from son that is held in acclaim (8)
I believe the answer is:
Here is my best explanation:
'like a broader smile' is the definition.
'son that is held in acclaim' is the subsidiary indication.
'son' becomes 's'.
'that is' becomes 'ie' ('i.e.' can be a synonym of 'that is').
'held in' indicates putting letters inside.
'acclaim' becomes 'cheer' (I've seen this before).
'sie' going into 'cheer' is 'cheesier'.
'from' is the link.