What does 'in character' mean?

[Our Tort System]

English Language Proficiency Tests, Advanced Level

ESL/EFL Test #643 "Prepositional Phrases - In, On, Out and Under (16)", question 2

Are you surprised that he bragged about himself all the way through dinner? That is definitely ......... character for him. He tends to brag about himself whenever he is around new people he doesn't know.

(a) in
(b) on
(c) out
(d) under

English Language Proficiency Tests, Advanced Level

ESL/EFL Test #643 "Prepositional Phrases - In, On, Out and Under (16)", answer 2

Are you surprised that he bragged about himself all the way through dinner? That is definitely in character for him. He tends to brag about himself whenever he is around new people he doesn't know.

Correct answer: (a) in

Your answer was: incorrect
Are you surprised that he bragged about himself all the way through dinner? That is definitely out character for him. He tends to brag about himself whenever he is around new people he doesn't know.
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Out OF character?

"Out character" sounds strange.
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If it's not easy, don't do it!
That's how I got where I am.

[Mister Micawber]

The answer is A, 'in character', so distractor C is not critical, but I agree that it could be a little more challenging, so I have added 'of' to C. It should appear with the next database update.
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Native English teacher at Mister Micawber's

[Beeesneees]

In character - typical behaviour (from him)
Out of character - unusual behaviour (from him)

In this instance, this is the way he always behaves around strange people so the answer is 'in character' as the test indicates.
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Cheers m' dears!