Righty

google

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Old English riht (adjective and noun), rihtan (verb), rihte (adverb), of Germanic origin; related to Latin rectus ‘ruled’, from an Indo-European root denoting movement in a straight line.

wiktionary

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right +‎  -y

etymonline

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righty (n.)

"right-handed person," 1949, especially in baseball, from right (adj.2) + -y (3).