Cocky

google

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mid 16th century (in the sense ‘lecherous’): from cock1 + -y1.

wiktionary

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From cock(“male domestic chicken”) +‎ -y(suffix forming adjectives with the sense of ‘having the quality of’). [1]

From cock(“male domestic chicken”) +‎ -y( diminutive suffix). [2]

The noun is derived from cock(atoo) +‎ -y( diminutive suffix). [3] The verb is derived from the noun. [4]

etymonline

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cocky (adj.)

"arrogantly pert," 1768; originally "lecherous" (1540s); from cock (n.1) + -y (2). Related: Cockiness.