Mentally sluggish
English: lumpish, lumpen, unthinking
unthinkingEnglish
unthinking, lumpen, lumpish, thoughtless, thoughtlessly
Adjective
Not exhibiting or characterized by careful thought
English: unreflective, unthinking, unthoughtful
Without care or thought for others, `Let them eat cake'"
English: thoughtless, uncaring, unthinking
Adverb
In a thoughtless manner
English: thoughtlessly, unthinkingly, unthinking