To do by guessing, to improvise.
To play (an instrument) or sing or to learn music without reading or memorizing sheet music; to learn a language without instruction.
Suitable to effect some desired end or the purpose intended.
Governed by self-interest, often short-term self-interest.
Affording short-term benefit, often at the expense of the long-term.
A method or means for achieving a particular result, especially when direct or efficient; a resource.