"Dost about it" is an old-fashioned phrase which means "to be concerned about something". If you're looking for synonyms to replace this phrase in your writing or conversation, you could use "care about", "worry over", "mind", "be troubled with", "be bothered by", "be interested in", "take notice of", "pay attention to", "be affected by", or "think deeply about". These different phrases can help you convey the same meaning and add variety to your language. Remember that language is always evolving, and it's okay to update your vocabulary to fit contemporary usage.