retard
re-tard
verb
To delay or slow the progress, development, or achievement of something.
"Poor funding can retard scientific research."
noun
An extremely offensive and derogatory term for a person with an intellectual disability.
"The word 'retard' is now considered a slur."
Thesaurus
Synonyms: cretin, changeling, half-wit, imbecile, idiot, moron, slow down, slow up, slow, decelerate, check, delay
Antonyms: accelerate, quicken, speed, speed up