1. (p. pr. & vb. n.) of Trail.

2. (a. & vb. n.) from Trail.

bugging chase chasing cloak-and-dagger work consecutive counterespionage counterintelligence dogging electronic surveillance espial espionage follow follow-up following heeling hounding hue and cry hunting intelligence intelligence work military intelligence observation prosecution pursual pursuance pursuing pursuit quest searching secret police secret service seeking sequel sequence series shadowing spying stakeout stalking succeeding surveillance tailing tracking tracking down wiretap wiretapping