: only by a very small amount The snake moved ever so slightly.

What does it mean to say ever so?

: very Thank you ever so much.

Do you hyphenate ever so slightly?

When Never to Use a Hyphen (plus exceptions)

But when you are using a whole phrase as an adjective, you might use hyphens all the same: “The ever-so-slightly embarrassed salesman continued with his pitch.” Compounds with prefixes such as “pre”, “post” or “mid” are usually used in the closed form: Postpartum.