verb (v)

• increase in extent or intensity(verb.change)

  Synonym:
  escalate, step up
  Antonym:
  de-escalate, step down, weaken
  

  source: wordnet30
• make more intense, stronger, or more marked(verb.change)

  Synonym:
  compound, deepen, heighten
  

  source: wordnet30
• become more intense(verb.change)

  Synonym:
  deepen
  

  source: wordnet30
• make the chemically affected part of (a negative) denser or more opaque in order produce a stronger contrast between light and dark(verb.change)

  source: wordnet30
• To render more intense; as, to intensify heat or cold; to intensify colors; to intensify a photographic negative; to intensify animosity.(verb)

  source: webster1913
• To become intense, or more intense; to act with increasing power or energy.(verb)

  source: webster1913