From Bulbapedia, the community-driven Pokémon encyclopedia.
A Lady in Suit (Japanese: スーツのおねえさん Lady in Suit) is a type of Pokémon Trainer that first debuted in the Generation III games, appearing in Pokémon Colosseum. They are women in their mid-20's in business suits. Like many of Orre's trainer classes, they don't specialize in any particular strategy or Pokémon.
While they reappeared in Pokémon XD: Gale of Darkness, the title "Lady in Suit" was replaced by Beauty.