I would assume that dextrous is a variation of dexterity.
After consulting my dictionary (I believe research has won the day on this one), it describes dextrous as something that is "done with dexterity." However, the latin root for the word "dextr-" means "on the right." So I understand how you came to that conclusion.
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Most Subtle Official Straightman of the Laughing Hyenas -- Grammarian Brigade.
"The only medicine for suffering, crime, and all the other woes of mankind, is wisdom." -- Thomas Huxley