The rule is, you should try to explain your new-learned words in English on your own. After this step you should compare your explanation with the explanation in English-to-English dictionary and see what's the difference

thereafter

My explanation: from then on

Dictionary: from a specified time onward; from then on

repulsive

My explanation: disgusting

Dictionary: causing repugnance or aversion; disgusting

crop up

My explanation: appear suddenly

Dictionary: to appear unexpectedly or occasionally

deliberate

My explanation: do something with enough consideration

Dictionary: arising from or marked by careful consideration