I as in …

Ice

Ice Cream

Iceberg

ID

Idea

Idiot

Ignorance

Ill

Immaturity

Import

Impossible

Impression

Improvement

Incest

Inch

Increase

Indian

Infection

Infinite

Information

Inheritance

Inside

Instructor

Instrument

Intensive

Interest

Internet

Interrupt

Interview

Invention

Investigation

Investment

IQ

Ir

Irish

Iron

Island

Italian