1. jackleg - Noun
2. jackleg - Adjective
(US) Amateur, untrained; incompetent.
(US) Dishonest, unscrupulous.
(US) Ineptly built or operated; makeshift.
A type of drill operated by means of compressed air.
(US) An amateur; an untrained or incompetent person.
(US) A shyster or con artist; a gambler who cheats; a generally dishonest or reprehensible person.
Source: en.wiktionary.org