improvised

/ɪmˈprɑvˌaɪzd/
adjective
  1. Made or done using whatever is available, without advance preparation.
    • She gave an improvised speech when the main speaker didn't show up.
    • The campers built an improvised shelter from branches and leaves.
    • They used a wooden crate as an improvised table for the picnic.
Antonyms