A vagrant is someone who is homeless and poor and may wander from place to place. In fiction a vagrant often is a criminal, but a real-life vagrant might just be a person who has lost a job and family and lives off the streets with help from charity.
Many synonyms for vagrant imply laziness and criminal behavior, such as "bum," "tramp," and "vagabond," and some vagrants do make money through crime. Often, though, a vagrant is a down-on-his-luck person who has lost work, family, or health and lives on the streets. European roots for vagrant point to "wander" or "wander about," and a vagrant is a wanderer — a man or woman without a place to call home.