UK:*UK and possibly other pronunciationsUK and possibly other pronunciations/ˈɒpətjuːnlɪ/

WordReference Random House Learner's Dictionary of American English © 2020
op•por•tune /ˌɑpɚˈtun, -ˈtyun/USA pronunciation   adj. 
  1. correct or right for a certain purpose or aim;
    apt:an opportune comment.
  2. occurring or happening at a good or appropriate time;
    well-timed:an opportune appearance at the press conference.
See -port-.
WordReference Random House Unabridged Dictionary of American English © 2020
op•por•tune  (op′ər to̅o̅n, -tyo̅o̅n),USA pronunciation adj. 
  1. appropriate, favorable, or suitable:an opportune phrase for the occasion.
  2. occurring or coming at an appropriate time;
    well-timed:an opportune warning.
op′por•tunely, adv. 
op′por•tuneness, n. 
  • Latin opportūnus convenient, equivalent. to op- op- + portu-, stem of portus access, port1 + -nus adjective, adjectival suffix (u lengthened as in tribūnus tribune)
  • late Middle English 1375–1425
    • 1.See corresponding entry in Unabridged apt;
      fortunate, propitious.
    • 2.See corresponding entry in Unabridged convenient.
      Opportune, seasonable, timely refer to something that is particularly fitting or suitable for a certain time.
      Opportune refers to something that is well-timed and meets exactly the demands of the time or occasion:an opportune remark.Something that is
      seasonable is right or proper for the time or season or occasion:seasonable weather.Something that is
      timely occurs or is done at an appropriate time, esp. in time to meet some need:timely intervention.

'opportunely' also found in these entries (note: many are not synonyms or translations):

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