sarcasm (n.), sarcastic (adj.)*:
"First, situations may be ironic, but only people can be sarcastic. Second, people may be unintentionally ironic, but sarcasm requires intention. What is essential to sarcasm is that it is overt irony intentionally used by the speaker as a form of verbal aggression."
「首先，『某些情況』可以是 ironic 的，但只有人才會是 sarcastic。其次，人無意中會 ironic，但 sarcasm 一定是故意的。Sarcasm 的前提是公然 irony，而且說者是故意把它當作一種言語上的攻擊。」
（資料來源：John Haiman, Talk Is Cheap: Sarcasm, Alienation, and the Evolution of Language. Oxford Univ. Press, 1998）
So basically sarcasm can only be applied to people, and it must be intentional. A sarcastic remark, in other words, has a purposefully malicious nature; at the very least, it should be teasing in a slightly abrasive way. Irony, on the other hand, can be unintentional.
所以基本上，sarcasm 只適用於人，且必須是故意的。換句話說，言論 sarcastic 是有目的地懷著惡意；最起碼應該是以有點傷人的方式來揶揄。另一方面，Irony 則可以是無意的。.
irony (n.), ironic (adj.)**:
"the discrepancy between what is said and what is meant, what is said and what is done, what is expected or intended and what happens, what is meant or said and what others understand"
satire (n.), satirical (adj.)***:
1. the use of irony, sarcasm, ridicule, or the like, in exposing, denouncing, or deriding vice, folly, etc.
2. a literary composition, in verse or prose, in which human folly and vice are held up to scorn, derision, or ridicule.
3. a literary genre comprising such compositions.
1. 運用 irony、sarcasm、ridicule（奚落）或類似的手法來揭發、譴責或嘲弄惡行、愚行等。
Satire is therefore primarily a literary exercise in which human weaknesses and social institutions are magnified and made fun of.