reasonable suspicion n:
an objectively justifiable suspicion that is based on specific facts or circumstances and that justifies stopping and sometimes searching (as by frisking) a person thought to be involved in criminal activity at the time see also reasonable cause at cause compare probable cause at cause, terry stop NOTE: A police officer stopping a person must be able to point to specific facts or circumstances even though the level of suspicion need not rise to that of the belief that is supported by probable cause. A reasonable suspicion is more than a hunch.
Source: Merriam-Webster's Dictionary of Law ©1996. Merriam-Webster, Incorporated. Published under license with Merriam-Webster, Incorporated.