In lang=en terms the difference between harness and groom
is that
harness is to capture, control or put to use while
groom is to attempt to gain the trust of a minor or adult with the intention of subjecting them to abusive or exploitative behaviour such as sexual abuse, human trafficking or sexual slavery.
As nouns the difference between harness and groom
is that
harness is (countable) a restraint or support, especially one consisting of a loop or network of rope or straps while
groom is a man who is about to become or has recently become part of a married couple short form of bridegroom or
groom can be a person who cares for horses.
As verbs the difference between harness and groom
is that
harness is to place a harness on something; to tie up or restrain while
groom is to attend to one's appearance and clothing.