ism tafdheel

Assalamu Alaikum wa rahmatuLLAHI wa barakatuHU wa maghfiratuHU,

I was wondering if ism-tafdheel is ghair munsarif....I think it is, because it has 2 sabab of manaa'sarf: one, wasfiyyat and two, wazn-e-fail. I only need to confirm if it really is ghair munsarif.....

JazakumULLAH khair
Wassalam ma'al-ikram