verb (v)

• perform without preparation(verb.creation)

  Synonym:
  ad-lib, extemporise, extemporize, improvize
  

  source: wordnet30
• manage in a makeshift way; do with whatever is at hand(verb.social)

  Example:
  After the hurricane destroyed our house, we had to improvise for weeks.
  

  Synonym:
  extemporize
  

  source: wordnet30
• To compose, recite, or sing extemporaneously, especially in verse; to extemporize; also, to play upon an instrument, or to act, extemporaneously.(verb)

  source: webster1913
• To produce or render extemporaneous compositions, especially in verse or in music, without previous preparation; hence, to do anything offhand.(verb)

  source: webster1913