Webster's Revised Unabridged Dictionary · 1913

Twig

Twig (twig) , transitive verb

[Compare Tweak.]

To twitch; to pull; to tweak. [Obsolete or Scottish]

Twig , transitive verb

[Gael. tuig, or Ir. tuigim I understand.]

1.
To understand the meaning of; to comprehend; as, do you twig me? [Colloquial] — Marryat
2.
To observe slyly; also, to perceive; to discover.
Now twig him; now mind him. — Foote
As if he were looking right into your eyes and twigged something there which you had half a mind to conceal. — Hawthorne

Twig , noun

[Anglo-Saxon twig; akin to Dutch twijg, Old High German zwīg, zwī, German zweig, and probably to English two.]

A small shoot or branch of a tree or other plant, of no definite length or size.
The Britons had boats made of willow twigs, covered on the outside with hides. — Sir W. Raleigh
Collocations (3)
Twig borer (Zoology) , any one of several species of small beetles which bore into twigs of shrubs and trees, as the apple-tree twig borer (Amphicerus bicaudatus).
Twig girdler (Zoology) , See Girdler, 3.
Twig rush (Botany) , any rushlike plant of the genus Cladium having hard, and sometimes prickly-edged, leaves or stalks. See Saw grass, under Saw.

Twig , transitive verb

To beat with twigs.