'slacker' originates from English, specifically formed from the adjective 'slack' plus the agentive suffix '-er', where 'slack' meant 'loose, not tight' (later 'lax, negligent').

'slacker' developed in modern English by adding '-er' to 'slack'; 'slack' itself comes from Old Norse 'slakr' (meaning 'loose' or 'slack') via Middle English 'slak'.

Initially related to physical looseness or lack of tension ('slack'), the sense shifted toward moral or behavioral laxness; 'slacker' came to mean 'one who is negligent or idle' (early 20th century).