'Underline' definitions:

Definition of 'underline'

From: WordNet
noun
A line drawn underneath (especially under written matter) [syn: underscore, underline]
verb
Give extra weight to (a communication); "Her gesture emphasized her words" [syn: underscore, underline, emphasize, emphasise]
verb
Draw a line or lines underneath to call attention to [syn: underline, underscore]

Definition of 'Underline'

From: GCIDE
  • Underline \Un`der*line"\, v. t.
  • 1. To mark a line below, as words; to underscore. [1913 Webster]
  • 2. To influence secretly. [Obs.] --Sir H. Wotton. [1913 Webster]
  • 3. Emphasize or call attention to; highlight; as, Long waits at the emergency room underline the need for a larger hospital.
  • . [JG]