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1711, "that concerns, important," from interest (v.). Meaning "so as to excite interest" is from 1768. Related: Interestingly. Euphemistic phrase interesting condition, etc., "pregnant" is from 1748.
1. Said of a problem that, although nontrivial, can be solved simply by throwing sufficient resources at it.
2. Also said of problems for which a solution would neither advance the state of the art nor be fun to design and code.
Hackers regard uninteresting problems as intolerable wastes of time, to be solved (if at all) by lesser mortals. *Real* hackers (see toolsmith) generalise uninteresting problems enough to make them interesting and solve them - thus solving the original problem as a special case (and, it must be admitted, occasionally turning a molehill into a mountain, or a mountain into a tectonic plate).
See WOMBAT, SMOP. Compare toy problem. Oppose interesting.