Asininity is a related term of brainlessness.
As nouns the difference between asininity and brainlessness
is that asininity is (uncountable) the quality of being asinine; obstinate stupidity while brainlessness is the state or condition of being brainless.
asininity
English
Noun
(uncountable) The quality of being asinine; obstinate stupidity
(countable) An asinine remark, behaviour, etc.
brainlessness
English
Noun
(-)
The state or condition of being brainless.