1. Proving directly.

Nuttall's Standard dictionary of the English language By Nuttall, P.Austin

• dietic,
• seictic,
• xeictic,
• ceictic,
• feictic,
• reictic,
• eeictic,
• dwictic,
• dsictic,
• ddictic,
• drictic,
• d4ictic,
• d3ictic,
• deitic,
• diectic,
• deicctic,
• deiktic,
• dicetic,
• deictick,
• dyeictic

• deistic.

The adjective form of the word "deictic" is "deictic". The word itself can function as both a noun and an adjective.

The plural form of the word "deictic" is "deictics".

The singular form of the word "deictic" is "deixis"