Suspicion refers to the feeling or belief that someone is guilty of doing something wrong or illegal, even without having concrete evidence. It can also indicate a sense of doubt or mistrust towards someone or something. When you have a suspicion, you aren't entirely convinced of the truth or reliability of a person, situation, or statement.
The word "suspicion" comes from the Middle English "suspicioun," which is derived from the Old French "suspicion," and ultimately from the Latin "suspicio," meaning "a looking up" or "a mistrust," from "suspicio" (to look up or to mistrust).