1. impossible to describe exactly or give an exact meaning to

Examples

• There was an undefinable quality about her that made everyone feel comfortable.
• The painting evoked an undefinable sense of melancholy.
• He felt an undefinable unease as he walked through the empty house.
• The fragrance had an undefinable sweetness that reminded her of childhood.
• There’s something undefinable about great art that moves people deeply.
• The atmosphere in the old library was undefinable but somehow magical.