Of a problem, mystery, crime or puzzle: still without an answer, even after people have tried. The word carries the trying inside it — an unsolved murder is one the police worked on and failed to close; an unsolved problem in maths is one that clever people have attacked for years. That is why it feels heavier than 'not answered yet'. It sits before the noun most of the time (an unsolved case, unsolved questions) but also after be: 'the crime remains unsolved'. Note the small grammar point that trips learners: unsolved describes the problem, never the person — you cannot say 'I was unsolved'. Compare unresolved, which is close but used more for arguments, feelings and situations that have not been settled (an unresolved dispute, unresolved anger), while unsolved wants a puzzle with a hidden answer.