Green’s Dictionary of Slang

mitt v.

[mitt n.]

1. [1900s–50s] (US) to punch.

2. [1900s–60s] (also mit) to shake hands, or to press something into someone’s hand, e.g., a bribe.

3. [1910s] (US) to pick up.

4. [1910s–50s] (US Und.) to handcuff, to arrest.

5. [1930s–40s] to wave to.

In phrases

mitt in (v.)

[1900s–50s] (US Und.) to inveigle someone into a cheating card game.

In exclamations

mitt me! (also mit me!)

[1930s–40s] (US) shake hands, esp. in context of congratulations.