unclear, ill-defined, unreadable, uncomprehensible, undecipherable, obscure, illegible, incomprehensible, vague.
I was sure that this ring of flame whirled as well as floated in the air; the motion and the sound, alike indecipherable,
were one and the same to me.
The remainder of it was merely an agitated, almost indecipherable
farewell to me.
The design is sometimes almost indecipherable,
for the poet draws in silver upon white.