Tweak Definition

twēk

tweaked, tweaking, tweaks

verb

tweaked, tweaking, tweaks

To give a sudden, twisting pinch to (someone's nose, ear, cheek, etc.)

Webster's New World

To pinch, pluck, or twist sharply.

Tweaked her sister's ear.

American Heritage

To adjust or modify slightly, so as to improve performance, efficiency, etc.; fine-tune.

Webster's New World

To make fun of; tease.

American Heritage

To behave in an agitated or compulsive manner, especially when under the influence of a stimulant drug.

American Heritage

Synonyms:

noun

tweaks

Such a pinch.

Webster's New World

A minor adjustment or modification.

Webster's New World

A teasing remark or action; a joke.

American Heritage

Wiktionary

Synonyms:

Other Word Forms of Tweak

Singular:

tweak

Plural:

Probably variant of dialectal twick from Middle English twikken from Old English twiccian

From American Heritage Dictionary of the English Language, 5th Edition
From Middle English twikken, from Old English twiccian (“to pluck"), cognate with twitch.

From Wiktionary