It stems from cocksure
- Abbreviation of cockatoo, especially when talking to such a bird, as in "hello cocky".
#: 2005: Visit the local store at Coles Bay and you're greeted by a talking cocky called Jim. — w:Australian Broadcasting Commission|Australian Broadcasting Commission, The World Today program, Town seeks environmental accreditation, 5 August 2005 1
- AU colloquial A farmer.
#: And stories in the bush may not seem relevant in the big smoke, but try telling that to a cocky. — Shelley Horton, w:Australian Broadcasting Commission|Australian Broadcasting Commission Media Dimensions program, episode 15 2
- overly self-confident up to a point where you're kidding yourself of your abilities.
Finnish: pÃ¶yhkeÃ¤, kopea, ylimielinen