big noun phrase ▶ big I am a person of great self-importance UK Variously: to be the big I am, to give it the big I am, to play the big I am; often with initial capitals.
— Ralph Steadman, TheBigIAm, 1988
He came up here about six months ago, playing the Big I Am, so he was. — Tony Black, PayingForIt, p. 209, 2008