Alternative dialogue words you could use instead of the word…

Plain

As an Adjective

Specifically meaning clear, firm, honest, straight, to the point of communication

Aboveboard

Abrupt

Artless

Bluff

Blunt

Brusk

Brusque

Candid

Crusty

Curt

Direct

Ernest

Forthcoming

Forthright

Foursquare

Frank

Free hearted

Freespoken

Guileless

Gruff

Honest

Impertinent

Impolite

Inconsiderate

Ingenious

Innocent

Naive

Natural

Open

Openhearted

Out front

Outspoken

Plainspoken

Point blank

Real

Rude

Sharp

Sincere

Straight

Straightforward

Tactless

Thoughtless

True

Truthful

Unaffected

Uncivil

Undesigned

Undiplomatic

Ungracious

Unguarded

Uninhibited

Unmannerly

Unpretending

Unpretentious

Unreserved

Unrestrained

Unsuitable

veracious

Vocal

Vociferous