·vt To handle awkwardly.
II. Thumb ·vt To play with the thumbs, or with the thumbs and fingers; as, to thumb over a tune.
III. Thumb ·vi To play with the thumb or thumbs; to play clumsily; to Thrum.
IV. Thumb ·noun The short, thick first digit of the human hand, differing from the other fingers in having but two phalanges; the pollex. ·see Pollex.
V. Thumb ·vt To soil or wear with the thumb or the fingers; to soil, or wear out, by frequent handling; also, to cover with the thumb; as, to thumb the touch-hole of a cannon.