The term originates in the Dungeons & Dragons (D&D) game, where it originally referred to a Githyanki fighter/wizard combination. Gish is still an official term used in D&D referring to this, but is also used to refer to any character who has a martial/spellcasting combination of abilities.
gish (plural gishes)
- (fantasy role-playing games) A character that is skilled in both physical combat and the use of magic.
- Most gishes use their magical abilities to increase their own personal combat abilities (known as "buffing").
- (slang) An outsider.
From the root -GIZH (“make a motion with a sticklike object”).