intensify (English)

Where does "intensify" come from?

The English verb 'intensify' was formed by combining the adjective 'intense' with the verbal suffix '-ify'[1]. The root adjective 'intense' traces back through Late Middle English and Old French 'intense' to the Latin 'intēnsus', meaning 'strained, stretched tight'[2]. This Latin participle stems from the verb 'intendō', formed from 'in-' combined with 'tendō'[5]. Ultimately, 'tendō' reaches back to Proto-Indo-European '*tend-' or '*ten-', meaning 'to extend, stretch'[4][6].

Open questions

• The Proto-Indo-European root involves an uncertain suffix attached to the base *ten-. [4]

Full etymology tree

• intensify (English), 'To render more intense.'
  • affix intense (English), 'Of a characteristic: extreme or very high or strong in degree; severe; also, excessive, towering.'
    • inherited intens (Late Middle English)
      • borrowed intense (Old French)
        • borrowed intensus (Latin), 'intent, eager'
          • derived intendo (Latin), 'to stretch out; to strain'
            • prefix in- (Latin), 'Prepositional prefix, generally attached to verbs to derive new verbs with a range of meanings.'
            • affix tendo (Latin), 'to stretch, stretch out, distend, extend'
              • inherited *tendō (Proto-Italic), 'to stretch'
                • inherited *ténd-e-ti (Proto-Indo-European)
                  • derived *tend- (Proto-Indo-European), 'to stretch, extend'
                    • derived *ten- (Proto-Indo-European), 'to stretch, extend'
                    • suffix *-d(H)- (Proto-Indo-European)
      • borrowed intensus (Latin), 'intent, eager'
        • derived intendo (Latin), 'to stretch out; to strain'
          • prefix in- (Latin), 'Prepositional prefix, generally attached to verbs to derive new verbs with a range of meanings.'
          • affix tendo (Latin), 'to stretch, stretch out, distend, extend'
            • inherited *tendō (Proto-Italic), 'to stretch'
              • inherited *ténd-e-ti (Proto-Indo-European)
                • derived *tend- (Proto-Indo-European), 'to stretch, extend'
                  • derived *ten- (Proto-Indo-European), 'to stretch, extend'
                  • suffix *-d(H)- (Proto-Indo-European)
  • suffix -ify (English), 'Forms transitive verbs meaning "to make" from adjectives and nouns.'

Ancestors

• intense (English)

Cognates and doublets

• intensifier (French)

Descendants and derived words

• reintensify (English)

Sources

1. intensify (English) - Wiktionary
2. intense (English) - Wiktionary
3. intensus (Latin) - Wiktionary
4. tend- (Proto-Indo-European) - Wiktionary
5. intendo (Latin) - Wiktionary
6. tendo (Latin) - Wiktionary

Updated October 2026

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Etymology data from Wiktionary, CC BY-SA 4.0 · About Miraris