Tweak

From Middle English twikken, from Old English twiccian ("to pluck"), cognate with twitch.

Full definition of tweak

(plural tweaks)

A sharp pinch or jerk; a twist or twitch.a tweak of the nose.
Trouble; distress; tweag.
A slight adjustment or modification.He is running so many tweaks it is hard to remember how it looked originally.
(obsolete, slang) A prostitute.

1638, Richard Brathwait, Barnabae Itinerarium: or Drunken Barnaby's four journeys to the north of England : In latin and english metre, Thomas Gent (1852), page 113:â€¦ Thence to Bautree, as I came there,
From the bushes near the lane, there
Rush'd a tweak in gesture flanting
With a leering eye, and wanton :
But my flesh I did subdue it
Fearing lest my purse should rue it.

(transitive) To pinch and pull with a sudden jerk and twist; to twitch.
to tweak the nose.
(transitive, informal) To adjust slightly; to fine-tune.
If we tweak the colors towards blue, it will look more natural.

2013-08-03, Boundary problems, Economics is a messy discipline: too fluid to be a science, too rigorous to be an art. Perhaps it is fitting that economistsâ€™ most-used metric, gross domestic product (GDP), is a tangle too....But as a foundation for analysis it is highly subjective: it rests on difficult decisions about what counts as a territory, what counts as output and how to value it. Indeed, economists are still tweaking it.

(transitive) To twit or tease.
(intransitive, US, slang) To abuse methamphetamines, especially crystal meth.
(intransitive, US, slang) To exhibit symptoms of methamphetamine abuse, such as extreme nervousness, compulsiveness, erratic motion, excitability; possibly a blend of twitch and freak.
(intransitive, US, slang) To exhibit extreme nervousness, evasiveness when confronted by law enforcement or other authority (e.g., customs agents, border patrol, teacher, etc.), mimicking methamphetamine abuse symptoms.