I. thumb 1 /θʌm/ BrE AmE noun [countable]
[ Language: Old English ; Origin: thuma ]
1 . the part of your hand that is shaped like a thick short finger and helps you to hold things:
a baby sucking its thumb
She held the coin carefully between finger and thumb.
2 . the part of a ↑ glove that fits over your thumb
3 . be all fingers and thumbs British English , be all thumbs American English informal to be unable to do something in which you have to make small careful movements with your fingers:
Would you do up these buttons for me? I seem to be all thumbs today.
4 . the thumbs up/down informal when an idea or plan is officially accepted or not accepted:
The project was finally given the thumbs up.
Her performance got the thumbs down from the critics.
5 . be under sb’s thumb to be so strongly influenced by someone that they control you completely:
He was still under his father’s thumb.
⇨ rule of thumb at ↑ rule 1 (8), ⇨ stand/stick out like a sore thumb at ↑ sore 1 (6)
II. thumb 2 BrE AmE verb
1 . thumb a lift British English , thumb a ride American English informal to persuade a driver of a passing car to stop and take you somewhere, by putting your hand out with your thumb raised:
I thumbed a lift into town.
2 . thumb your nose at somebody/something to show that you do not respect rules, laws etc or you do not care what someone thinks of you:
a chance to thumb his nose at the college authorities
thumb through something phrasal verb
to look through a book, magazine etc quickly:
I began thumbing through the pages of a gardening catalogue.