Plain

a plain sailing

as plain as day/as the nose in your face/as pikestaff

as plain as the nose in your face

Crying is the refuge of plain women but the ruin of pretty ones.

From now on it’s all plain sailing

good plain cooking

He told me the plain truth

I told him my opinion in plain words.

in plain English

in plain language

in plain view

It’s quite plain to me

plain cooking

plain sailing

plain vanilla