how do you tell identical words apart??

Okay so I was trying to learn the word for 'immediately' or like 'right now' and there are like FIFTY different ways to say it? and then I got distracted looking at samurai history which is cool but anyway. how do you guys memorize these antonyms because my brain literally melts when two words mean the exact same thing but they dont??? like one is for politics and one is for cleaning or something? idk i lost my train