See us trembling with tiger, becoming more courageous (7)

I believe the answer is:

gutsier

'more courageous' is the definition.
('gutsy' can be a synonym of 'courageous')

'see us trembling with tiger' is the wordplay.
'trembling with' indicates an anagram.
'us' anagrammed with 'tiger' makes 'GUTSIER'.

'becoming' is the link.

(Another definition for gutsier that I've seen is " More courageous".)

I've seen this clue in The Telegraph.

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