Definition: Mercenary has a double status as an adjective and a noun. The adjective definition refers to the actions of the noun. In other words, you can call someone a mercenary and also say they are acting as a mercenary. The core definition is hired in the service of others for nothing more than money.
As the noun, a mercenary is a hired soldier. As an adjective mercenary describes the deplorable actions mercenaries take for money.
Etymology: The noun form of mercenary comes from the Latin word “merces” meaning reward.
The adjective form comes from the Latin word “mercenarius” which means being a soldier just for the pay. Thus, a mercenary is rewarded for being a soldier and hated for taking soldier-like actions just for the reward. Note the two synonyms listed below.
In a Sentence
As the warrior swung his sword from side to side, his true mercenary nature came out.
Sitting on a lone horse behind the setting sun, the leader called out in unity to his mercenary soldiers.
In undeniably mercenary actions, the county sheriffs led the homeless camp cleanup efforts, even as the dislodged residents disputed and attempted to get things away from the excavator.