From The Collaborative International Dictionary of English v.0.48 [gcide]:
Stalker \Stalk"er\ (st[add]k"[~e]r), n.
1. One who stalks.
[1913 Webster]
2. A kind of fishing net.
[1913 Webster]
From WordNet (r) 3.0 (2006) [wn]:
stalker
n 1: someone who walks with long stiff strides
2: someone who stalks game
3: someone who prowls or sneaks about; usually with unlawful
intentions [syn: prowler, sneak, stalker]