thumb
I
 /ˈθʌm/  noun  ,  pl   thumbs [  count  ]
  1 : the short, thick finger on the side of your hand
   a little girl sucking her thumb
   I accidentally cut my thumb.
  — see also green thumb
  2 : the part of a glove or mitten that covers a thumb
   My mitten has a hole in the thumb.
  all thumbs  (US)   ( or Brit   all fingers and thumbs)
   : extremely awkward or clumsy
    I'm all thumbs when it comes to wrapping packages.
  rule of thumb — see rule, 1
  stick out like a sore thumb — see sore, 1
  twiddle your thumbs — see twiddle
  under someone's thumb
   : under someone's control or influence
    He kept the employees under his thumb.
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II
  verb  , thumbs, thumbed, thumb·ing
   informal   : to ask for or get a ride in a passing vehicle by sticking out your arm with your thumb up as you stand on the side of the road : hitchhike
   [  + obj  ] I thumbed a ride/lift to school.
    He thumbed his way to New York.
   [  no obj  ] He thumbed across the country.
  thumb through [  phrasal verb  ]
   thumb through (something) : to turn the pages of (a book, magazine, etc.) quickly
    I thumbed through a magazine while I waited.
  thumb your nose at
   : to show very clearly that you do not like or care about (something)
    She thumbed her nose at my suggestions.
    They thumb their nose at the rules. [=they ignore the rules]
  thumbed  adj  
  — used in combination
   a well-thumbed book [=a book that has been used/read a lot]
   a much-thumbed copy of the rules