Lacking taste or savour: Tasteless. (Merriam – Webster)
Lacking in qualities that interest, stimulate, or challenge: Dull, Flat. (Merriam – Webster)
Not having a strong taste or character, or having no interest or energy. (Cambridge Dictionary)
If you describe food or drink as insipid, you dislike it because it has very little taste. (Collins Dictionary)
If you describe someone or something as insipid, you mean they are dull and boring. (Collins Dictionary)
Lacking flavour; weak or tasteless. (Oxford Dictionaries)
Insipid. Win Every Game.
Mundane vs Insipid – What’s the difference?