Some writers’ manuscripts always seem to need a little fixing up where these three words are concerned.

Touch up is a phrasal verb meaning to make some minor alterations to, as in “Debbie, touch up your makeup,” Dawn said. Here, Dawn is asking Debbie to perform a specific action.

Touchup, however, is a noun in which the action itself is considered a thing, as in Debbie gave her makeup a quick touchup. Here, the touchup is an object, specifically the altered makeup on Debbie’s face.

Touch-up means the same as touchup. Usually when people begin using a phrasal verb as a noun, a hyphen is placed between the two words to show you no longer are using it as a verb; over time, as this noun becomes common in our language, the tendency is to do away with the hyphen. The hyphenated version still lingers, however, usually in more formal writing.