To authenticate by means of belief; to surmise; to suppose to be true, especially without proof
We assume that, as her parents were dentists, she knows quite a bit about dentistry.
To take on a position, duty or form
Mr. Jones will assume the position of a lifeguard until a proper replacement is found.
To adopt a feigned quality or manner; to claim without right; to arrogate
He assumed an air of indifference
To receive, adopt (a person)
To adopt (an idea or cause)
An assumption.
Haughty; arrogant