The word 'stalker' is a transparent modern compound, formed from the verb 'stalk' and the agentive suffix '-er'. The verb 'stalk' itself has a long history, originating from the Old English stealcian, meaning 'to walk cautiously or stealthily', a sense closely tied to hunting or pursuing prey. This Germanic root evolved to emphasize a slow, deliberate, and often secretive approach. By the late 20th century, the specific application of this hunting metaphor to human behavior—describing someone who persistently and obsessively follows another—became cemented in the language, particularly through psychological and legal contexts. Thus, a 'stalker' literally denotes 'one who stalks', transforming an ancient term for a physical hunt into a modern concept of intrusive harassment.

Structure: stalk (follow stealthily) + er (agent noun suffix) stalk: From Old English stealcian (to walk stealthily), of Germanic origin; functional role: verbal root. er: From Old English -ere, an agent noun suffix; functional role: suffix denoting a person who performs an action.