Out and away from a starting point. When someone goes forth from a place, they leave it. Out of a place and goes on.
Onward or outward in place or space, forward is to come forth or go forth. If you declare that from today forth, you’ll pursue your dream of becoming a rodeo clown, it means you will work every day to make it happen.
Forth is defined as forward, beyond or out of hiding. An example of forth is all the people standing in front of a certain person in line are able to get in, from this person forth can enter.
Synonyms as out from, out of, and so on, ahead, forward, on, onward. “The snow is gone, and the flowers are ready to spring forth”.