Dreams dictionary: Thumb

Dreams dictionary: Interpretation 1
To see a thumb in your dream indicates that you need to get a grip on things. It is symbolic of power and ability. If you are giving the thumbs up, then it represents approval and that you are "okay" to proceed. If you are giving the thumbs down, then it means disapproval.
Dreams dictionary: Interpretation 2
To dream that you have no thumb denotes poverty and loneliness.
Dreams dictionary: Interpretation 3
To dream that you have an abnormally large thumb signifies a rapid rise to success.
Dreams dictionary: Interpretation 4
To dream that your thumb has a very long nail signifies that some negative force is luring you toward some illicit activity.
Dreams dictionary: Miller Dream Interpretation
To dream of seeing a thumb, foretells that you will be the favorite of artful persons and uncertain fortune. If you are suffering from a sore thumb, you will lose in business, and your companions will prove disagreeable. To dream that you have no thumb, implies destitution and loneliness. If it seems unnaturally small, you will enjoy pleasure for a time. If abnormally large, your success will be rapid and brilliant. A soiled thumb indicates gratification of loose desires. If the thumb has a very long nail, you are liable to fall into evil through seeking strange pleasures.