Circle: handomse/cute, loud/noisy, messy/dirty, awful/terrible, buddy/pal, dull/boring, angry/mad, happy/glad, tiny/little, strong/powerful
X out: Enormous/tiny, correct/wrong, asleep/awake, light/dark, easy/difficult, friend/enemy, quick/slow, love/hate.
We can't see the 2 on the bottom right (correct/??? and up/???), so I can't help with those.
A synonym is when 2 words are different, but mean smilar things (ex. love and adore, or huge and giant). An antonym is when 2 words are different and mean exact opposites of each other (ex. loud and quiet, or shiny and dull).