| hover |
| informer(noun, plant, agent, operative, mole) |
| inside agent(noun, expression, plant, agent, operative) |
| intelligencer(noun, plant, agent, operative, informer) |
| investigator(noun, plant, agent, operative, informer) |
| junket(trip, voyage, ride, excursion, spree) |
| keep(verb, cover, secure, observe, defend) |
| keep an eye on(verb, expression, idiom, cover, keep) |
| keep eyes open(verb, expression, idiom, keep, protect) |
| keep eyes peeled(verb, expression, idiom, keep, protect) |
| keep in view(verb, expression, idiom, cover, keep) |
| keep under surveillance(verb, expression, idiom, cover, keep) |
| keep watch over(verb, expression, idiom, phrasal verb, keep) |
| keeper(noun, watch, guard, champion, protector) |
| law |
| law enforcement |
| lighthouse |
| look after(verb, expression, cover, keep, secure) |
| look out(verb, expression, keep, protect, watch) |
| lookout man |