• lookeron,
• looker-on,
• lowokeron,
• lookerron,
• lokeron,
• lookern,
• lookaron,
• kooker on,
• pooker on,
• oooker on,
• lioker on,
• lkoker on,
• lloker on,
• lpoker on,
• l0oker on,
• l9oker on,
• loiker on,
• lokker on,
• lolker on,
• lopker on

The adjective form of the word "looker-on" is "spectatorial".

The plural form of "looker on" is "lookers-on"

The singular form of the word "looker on" is "looker on". The term "looker on" is already in singular form and refers to someone who observes an event or situation without participating in it.