1. Stupidity.

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

• stupiness,
• atupidness,
• ztupidness,
• xtupidness,
• dtupidness,
• etupidness,
• wtupidness,
• srupidness,
• sfupidness,
• sgupidness,
• syupidness,
• s6upidness,
• s5upidness,
• stypidness,
• sthpidness,
• stupiedness,
• stoopidness,
• stoupedness,
• stoupidness,
• stupedness

• stupid person,
• stupidly,
• stupidity,
• step-down,
• stop dead,
• step down.

The adjective form of the word "stupidness" is "stupid".

The plural of the "stupidness" can be the "stupidnesses".

The singular of the "stupidness" can be the "stupidness".