- 1undermine something to make something, especially somebody’s confidence or authority, gradually weaker or less effective Our confidence in the team has been seriously undermined by their recent defeats. This crisis has undermined his position. Recent changes have undermined teachers’ morale.
- 2undermine something to make something weaker at the base, for example by digging under it Word Origin Middle English: from under- + the verb mine, probably suggested by Middle Dutch ondermineren.Extra examples It ultimately undermined his ability to play. a terror attack intended to undermine the morale of citizens Recent changes have undermined teachers’ morale. The director saw this move as an attempt to undermine his authority. This crisis threatens to undermine the very foundations of social life.
BrE BrE//ˌʌndəˈmaɪn//; NAmE NAmE//ˌʌndərˈmaɪn//Verb Forms present simple I / you / we / they undermine
BrE BrE//ˌʌndəˈmaɪn//; NAmE NAmE//ˌʌndərˈmaɪn//he / she / it undermines
BrE BrE//ˌʌndəˈmaɪnz//; NAmE NAmE//ˌʌndərˈmaɪnz//past simple undermined
BrE BrE//ˌʌndəˈmaɪnd//; NAmE NAmE//ˌʌndərˈmaɪnd//past participle undermined
BrE BrE//ˌʌndəˈmaɪnd//; NAmE NAmE//ˌʌndərˈmaɪnd//-ing form undermining
BrE BrE//ˌʌndəˈmaɪnɪŋ//; NAmE NAmE//ˌʌndərˈmaɪnɪŋ//