unsolved

verb (used with object), solved, solv·ing.

1. to find the answer or explanation for; clear up; explain: to solve the mystery of the missing books.
2. to work out the answer or solution to (a mathematical problem).

adjective

1. not having been solved or explainedseveral unsolved murders

verb (tr)

1. to find the explanation for or solution to (a mystery, problem, etc)
2. maths
   1. to work out the answer to (a problem)
   2. to obtain the roots of (an equation)

v.late 14c., “to disperse, dissipate, loosen,” from Latin solvere “to loosen, dissolve; untie, release, detach; depart; unlock; scatter; dismiss; accomplish, fulfill; explain; remove,” from PIE *se-lu-, from reflexive pronoun *s(w)e- (see idiom) + root *leu- “to loosen, divide, cut apart” (see lose). The meaning “explain, answer” is attested from 1530s; for sense evolution, see solution. Mathematical use is attested from 1737. Related: Solved; solving.