1. To become twice as much.

2. To repeat often; to increase by repeated additions.

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

• redible,
• treouble,
• adouble,
• reptuble,
• republe,
• ddouble,
• deouble,
• redoubls,
• reedouble,
• reouble,
• reduble,
• redoube,
• reduoble,
• redoubel,
• redoubble,
• redoublee,
• re double,
• remoule,
• redubble,
• redduble

• readable,
• readably,
• redoubled.

The adverb form of the word "redouble" is "redoubly".

The adjective form of "redouble" is "redoubled".

The plural of the "redouble" can be the "redoubles".

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