A hard keeper or (British English) poor doer is a horse or other livestock animal that is naturally prone to be thin, will lose weight quickly, and has difficulty gaining weight.

The structure of big pharmaceutical companies, which do everything from basic research to manufacturing to parceling out samples to doctors, makes it naturally prone to use outsourcing.

Most women who want and anticipate having a baby are naturally prone to thinking in terms of having a well baby.

Many are naturally prone to want to hug and kiss everyone they meet.

Patients with primary biliary cirrhosis are mainly elderly women who are naturally prone to osteoporosis.

It is naturally prone to flooding during heavy rains.

As institutional boosters, Mr. Neuharth and Mr. Bartlett are naturally prone to caress their customers.

In this contest, the underdog is naturally prone to the nastiest manners, though as the 1988 Presidential campaign demonstrated, the overdog can bite, too.

Some people's joints are naturally prone to injury, and if they play often or long enough, they will develop tennis elbow.