Back up and Propping up

Back up verb - Move backwards from a certain position.

Propping up and back up are semantically related In some cases you can replace phrase "Propping up" with "Back up", this terms are similar.

Propping up noun - The act of propping up with shores.

Back up and propping up are semantically related in strengthen topic. Sometimes you can use "Back up" instead a verb phrase "Propping up".