Adjective opportune has 2 senses
  1. opportune - suitable or at a time that is suitable or advantageous especially for a particular purpose; "an opportune place to make camp"; "an opportune arrival"
    inopportune, ill-timed, ill timed, unseasonable, untimely, wrong, inconvenient
  2. favorable, favourable, opportune - at a convenient or suitable time; "an opportune time to receive guests"
    Antonym: inconvenient (indirect, via convenient)