A public executioner; = lockman .
Late 17th century; earliest use found in Fountainhall's Decisions. Apparently an alteration of lockman, after the genitive of lock.
A person employed to attend and maintain a lock on a canal or river.
Mid 19th century; earliest use found in New-Yorker. From the genitive of lock + man.
A male Rastafarian who wears dreadlocks.
1960s. From the plural of lock + man.