| bug(noun, verb, study, consider, examine) |
| tap(noun, verb, study, consider, examine) |
| intercept |
| eavesdrop(verb, bug, spy, listen, monitor) |
| listen in(verb, expression, phrasal verb, study, consider) |
| listening device(noun, expression, bug, hidden microphone) |
| surveillance(noun, scrutiny, investigation, following, shadowing) |
| be all ears(verb, expression, idiom, study, consider) |
| following(noun, adjective, bug, scrutiny, investigation) |
| observation(noun, scrutiny, investigation, shadowing) |
| pry(verb, study, consider, examine, review) |
| stakeout(noun, bug, scrutiny, investigation, monitor) |
| tailing(verb, scrutiny, investigation, shadowing) |
| wiretapping |
| beleaguer |
| bend an ear(verb, expression, idiom, bug, snoop) |
| bugging(noun, bug, scrutiny, investigation, monitor) |
| exploit |
| inquire(verb, study, consider, examine, review) |
| investigate(verb, check) |