(historical, usually in the plural) One of several men gathered at a thing, for example to settle a dispute over a debt.
Now if the debtor pleads that "I do not know the law but I will comply with whatever the thingmen think lawful," he [the creditor] must summon him before the thing after five nights, at the shortest, and five times five at the longest, if he knows when the thing is to meet; […] it is then the duty of the thingmen to decide the matter and to award him his money.
(historical, usually in the plural) (One of several) men serving as the army, particularly the mercenary army, (of a specific ruler).