Posthole and Sinkhole

Posthole noun - A hole dug in the ground to hold a fence post.

Sinkhole and posthole are semantically related. In some cases you can use "Sinkhole" instead a noun "Posthole".

Sinkhole noun - A depression in the ground communicating with a subterranean passage (especially in limestone) and formed by solution or by collapse of a cavern roof.

Posthole and sinkhole are semantically related. You can use "Posthole" instead a noun "Sinkhole".