The unimaginable nature is only for the identification of unimaginable God

132) Na svarupamudhaasutravadabhijnaanam .

(The unimaginable nature is only treated as characteristic for identification of unimaginable God like the yellow thread in the neck of a married lady standing for identification of her marriage).

Since no characteristic of God is known, God is treated as unimaginable. This very aspect of God helps us to detect His existence in a specific medium. Since this aspect of unimaginable nature helps us to detect His existence, it can be treated as an aspect equivalent to the characteristic though it need not be the real characteristic. The yellow thread of a married lady is never removed and hence can act as the identifying mark to be treated as a characteristic. But, this does not mean that the yellow thread itself is a part and parcel of her body like her leg or hand, which is the real characteristic. Hence, the inseparable mark of identification need not be a real characteristic.
Note:
Unimaginable nature is not a characteristic of God, but an associated characteristic which can be treated as a real characteristic. It is like the yellow thread of a married lady. It is not like her leg and hand which is her real characteristic. But just like leg or hand cannot be separated from the body, the yellow thread of the married lady is also not separated. It can be treated as real characteristic. But not actually real characteristic. It can be removed. If husband dies then it is removed. It is separable but as long as the husband is alive, it is never separated. So as long as the husband is alive the yellow thread can be treated as leg or hand. Thus inseparable associated characteristics can be treated as the real characteristic. Similarly the unimaginable nature is not a real characteristic but can be treated as a real characteristic for identification.