1. In opposite directions; at cross purposes.

2. The cross or signature of one who cannot write; a child's game played on slates.

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

• crisscross,
• xriss-cross,
• vriss-cross,
• friss-cross,
• driss-cross,
• ceiss-cross,
• cdiss-cross,
• cfiss-cross,
• ctiss-cross,
• c5iss-cross,
• c4iss-cross,
• cruss-cross,
• crjss-cross,
• crkss-cross,
• cross-cross,
• cr9ss-cross,
• cr8ss-cross,
• crias-cross,
• crizs-cross,
• crixs-cross

The adverb form of "criss-cross" is "crisscrossly".

The adjective form of the word "Criss-cross" is "crisscrossed".

The plural form of "Criss-cross" is "Criss-crosses"

The singular form of the word "criss-cross" is "criss-cross". The word does not change from singular to plural.