1. to think that something is smaller, less important, or less difficult than it really is

1. an estimate that is too low or inadequate

Examples

• Don't underestimate the difficulty of this math problem.
• The company underestimated the cost of the project by millions.
• Never underestimate your opponent in a chess match.
• The weather forecast was an underestimate of the storm's intensity.
• She tends to underestimate her own abilities.
• His initial underestimate led to serious budget problems.
• The coach warned the team not to underestimate their rivals.