The verb bolster means to support or increase something such as someone’s confidence or courage.

Synonyms are boost, strengthen, help, or reinforce.

The word origins from Old English bolster meaning “bolster, cushion, something stuffed so that it swells up” especially “a long, stuffed pillow”, from Proto-Germanic bolkhstraz (source also of Old Norse bolstr, Danish, Swedish, Dutch bolster, German polster).

His mother’s presence bolstered his weak will.

The country’s focus on good international relations has bolstered the economy.

That cunning politician needs to do something to bolster his image.