From The Collaborative International Dictionary of English v.0.48 [gcide]:
Wanderer \Wan"der*er\, n.
One who wanders; a rambler; one who roves; hence, one who
deviates from duty.
[1913 Webster]
From WordNet (r) 3.0 (2006) [wn]:
wanderer
n 1: someone who leads a wandering unsettled life [syn:
wanderer, roamer, rover, bird of passage]
2: a computer program that prowls the internet looking for
publicly accessible resources that can be added to a
database; the database can then be searched with a search
engine [syn: spider, wanderer]