The term 'indecipherable' is used to describe something that cannot be understood or interpreted. The crossword solutions for this term are 'ILLEGIBLE' (9 letters), 'ESOTERIC' (8 letters) and 'INCOHERENT' (10 letters). ILLEGIBLE means that something is not readable due to being written in a way that is difficult to decipher, such as handwriting that is too messy or faint. ESOTERIC refers to something that is known only by a select few and is not widely understood. INCOHERENT means that something is not logically connected or does not make sense. All three of these words can be used to describe something that is indecipherable.