In Spanish, "buenas tardes" is a common greeting used during the afternoon hours to say "good afternoon". However, there are a few synonyms that you can use to greet someone during the same time of day. Some alternatives to "buenas tardes" include "feliz tarde" which means "happy afternoon", "tardes buenas" which means "pleasant afternoons", or "bonita tarde" which means "beautiful afternoon". Additionally, you can use the more formal "me alegro de verle esta tarde" which translates to "I am pleased to see you this afternoon". No matter which synonym you use, it is important to always greet others politely and with respect.