Best Regards
Well, Properly, Suitably
adverb, expression
よろしく
よい is the first and last character of よ(ろし)い. They both mean Good. よろしく means Well. It's just the adverb form of good. よろしく can also mean Best Regards when used as a contraction of おろしくお願いします. お願い can mean Wish or Request. おろしくお願いします is highly contextual. It could mean Well Wishes (Best Regards), Please Treat Me Well, Please Kindly Fulfill My Request, and more.