1. problem - Noun
2. problem - Adjective
A question proposed for solution; a matter stated for examination or proof; hence, a matter difficult of solution or settlement; a doubtful case; a question involving doubt.
Anything which is required to be done; as, in geometry, to bisect a line, to draw a perpendicular; or, in algebra, to find an unknown quantity.
Source: Webster's dictionaryshe and her husband are having problems Source: Internet
it is always a job to contact him Source: Internet
urban problems such as traffic congestion and smog Source: Internet
one trouble after another delayed the job Source: Internet
what's the problem? Source: Internet
our homework consisted of ten problems to solve Source: Internet