1. Give extra weight to (a communication)
   - underscore, emphasize, emphasise [Brit] 
2. Draw a line or lines underneath to call attention to
   - underscore

1. A line drawn underneath (especially under written matter)
   - underscore

Derived forms: underlines, underlined, underlining

Type of: accent, accentuate, emphasise [Brit], emphasize, mark, punctuate, stress, stroke

Encyclopedia: Underline

• indescribably
• indestructibility
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• indeterminable
• indeterminably
• indeterminacy
• indeterminacy principle
• indeterminate
• indeterminateness
• indetermination
• index
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• index register
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• India