indefinable

/ˌɪndɪˈfaɪnəbəl/
adjective
  1. Impossible to describe or explain exactly.
    • There was an indefinable sadness in his voice.
    • She felt an indefinable sense of unease as she entered the room.
    • The smell of the old library had an indefinable charm.
Antonyms
What does "indefinable" mean? | whatsthatwordmean | whatsthatwordmean