A suspect is an individual or organisation that fits the basic criteria for a potential customer but has shown little or no engagement with your marketing efforts. In lead generation, suspects are identified early on, before any serious interest or qualification. They need further vetting to determine if they can be advanced to prospect status or disqualified entirely.
Scenario 1: A company compiles a list of attendees from a trade show who have not interacted further. Each attendee is considered a suspect until more engagement occurs.
Scenario 2: An IT manager at a target company is found on LinkedIn and fits the buyer profile, but has not responded to outreach. They remain a suspect.
See also: Prospect, Lead, Customer, Qualification.