Unintelligent (5)
'unintelligent' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for inane that I've seen before include "Idiotic" , "Vacuous, silly" , "Unintelligent" , "Foolish, fatuous" , "Dull-witted" .)
'unintelligent' is the definition.
(I know that unintelligent can be written as stupid)
This is all the clue.
(Other definitions for stupid that I've seen before include "Unintelligent, really thick" , "Senseless" , "(Seeming to be) lacking intelligence" , "Very silly" , "Obtuse" .)