What is the opposite of modest?

The opposite of modest depends on the context, but here are some possibilities:

In terms of behavior and attitude:

* Boastful

* Arrogant

* Conceited

* Showy

* Flamboyant

* Brash

* Pretentious

* Self-important

In terms of appearance:

* Extravagant

* Gaudy

* Opulent

* Lavish

* Showy

* Flashy

In terms of size or scale:

* Grand

* Imposing

* Massive

* Extensive

The best opposite for "modest" will depend on the specific situation and the meaning you want to convey.