During the match, I had to sub in for my injured teammate.

The navy deployed a sub to search for the missing submarine.

I need to find a substitute for the meeting tomorrow.

The sub-optimal decision I made cost me the job.

The case is sub judice, so we cannot discuss it at this time.

The company's profits are sub marginal.

They met sub rosa to discuss their secret plan.

Our sub conscious mind influences our thoughts and actions.

The hippo is a large, herbivorous mammal found in sub-Saharan Africa.