Kids sometimes play 'Cops and robbers'. How about crook?
A "brigand" is a criminal. Antonym means "opposite word", so an antonym for brigand might be "policeman" or "guard".
Policewoman
police woman
The opposite of first might be last, or the concept might have no opposite..... "Who was the first person to set foot on the moon?" has no opposite.
There might not be an opposite.
A good person, maybe a citizen or policeman. The opposite adjective could be legal, or laudable, or civil where it defines the two types of court cases.
The opposite of over might beundercontinuing
The opposite of girls might be women or boys.
The opposite of the verb measure might be not to measure, or to guess.
if someone is "full of bravery" then the opposite is "full of cowardice"
Depending on the context, the opposite might be unconcerned, uninterested, or unobtrusive.
The opposite side did win.