1. Gamma Delta Iota (ΓΔΙ) or God Damn Independent; a fictitious fraternity used by fraternity and sorority members to refer to people not affiliated with such organizations.

GDI (plural GDIs)

1. (computing, Microsoft, Microsoft Windows)
   (deprecated use of |lang= parameter) Initialism of en#English|{w (“Graphics Device Interface}”).
   .
2. (automotive) Initialism of gasoline direct injection fuel injection

• (fuel injection) PDI

1. (euphemistic, slang, rare) Abbreviation of goddamn#English|goddamn it.