There are several synonyms one can use for the phrase "transmitted by post." Some alternatives includes "mailed," "posted," "dispatched," "sent via mail," "delivered by post," and "forwarded through the mail." All of these phrases convey the same meaning as the original expression, which implies something being sent or delivered through the postal service. The use of synonyms is especially helpful when writing to avoid repetition or when trying to add variety and flavor to one's language. By incorporating different variations of the same phrase, one can add depth and variety to their writing, making it more engaging and fresh.