Laki is an actor, who plays the role of a detective on a TV show called Alolan Detective Laki (Japanese: アローラ探偵ラキ Alola Detective Laki), which Rotom and Professor Kukui like to watch. It is not known whether Laki is the actor's real name or just the name of the character he plays. Laki is very popular in the Alola region and even has his own merchandise, including blonde wigs styled after his own hair. Rotom likes to impersonate Laki and pretend to solve cases as well.
(Source: Bulbapedia)