從前從前，筆者看不起形容詞，因為 Adj 只有一種用法：「修飾名詞」，而且其用法和中文一樣，就是放到名詞前面就好。如今，用心了解之後才發現 compound adjective 超級複雜！此主題雖被分類為「advanced class」，但它的玩法和中文相似–將兩個字合在一起創造一個新的意思。因此筆者認為，就算高中以下的程度也一定能輕鬆掌握，必學！！
影片以「I saw a man eating an alligator VS I saw a man-eating alligator」來開頭，超級有趣！聽說 Shakespeare 很喜歡這種寫法，例如：jealousy is the green-eyed monster = jealousy is the monster with green eyes. 前者的寫法很像中文，也比較有韻味。本文蒐集筆者找到 YT 上講的最清楚（卻沒什麼人看）的教學影片，並筆記摘要，供大家參考利用。
筆者認為，複合形容詞的用法分為三種：
Adjective 基底：
a world-famous brand / a smoke-free store / ice-cold beer/ a gluten-free meal / a pet-friendly restaurant / a power-hungry dictator / a resonance-provocative story / a water-proof jacket / a mistake-prone boy P.S. proof 除了有證據的意思之外，還有「耐…的，防…的」的意思。例如 No household security devices are proof against (= protect completely against) the determined burglar (Cambridge).
此用法把「名詞 + Adj」打包，用名詞來修飾形容詞，使該形容詞更加強大＆更加戲劇化！其本體是 be 動詞的變形。例如： a world-famous brand = a brand which is famous around the world.
Noun 基底：
an open-minded person / sharp-toothed unkindness / a closed-minded person / an old-fashioned clothes / a bad-tempered child / an absent-minded person / a blond-haired girl / a broad-shouldered athlete / a cool-headed performer / a hot-headed principal /a middle-aged man / a well-intentioned remark / a cold-hearted robber / a high-skilled detective
此用法把 「Adj +名詞-ed」打包，使這個「形名包」被擁有！例如：an open-minded person = a person who has open mind. （open mind 被這個人所擁有）
a closed-minded person = a person who has closed mind 。其中 closed 是「被關上的」，利用被動式當形容詞，相當特別。如果單純使用 close，那意思會變成「親近的」或者「靠近的」，當然也就不能接 mind 了。
在 well-intentioned 的例子中，well 正常來說是 good 的副詞，所以這個用法似乎不是把 Adj & Noun 打包？事實上，well 也可以當形容詞使用，但意思會變成強調內在狀態（in a good or satisfactory state）的好，也可以用來形容「健康」，例如 He is not well。且注意，well 當形容詞時不可放在名詞前面。例如：He is a well man (X，不可放在 N. 前面)。
例外
noun 基底的例外非常多！然而請注意，通常英語裡面會產生「例外多」的原因，是很多人在用，錯的也多，結果習慣成自然……。總之，所謂的例外，反而是最重要的用法！
數量不加 ed => a six-hour operation / a three-week vacation / a ten-page book / a two-liter bottle / a five-story building / a one-way communication / multi-source feedback。（注意，若數字是描述外表的話，還是要加。例如：a one-eyed pirate / a three-legged insect / a two-faced traitor）
順序不加 ed => a first-class passenger / first-hand information / a first-time user / a second-hand book / a second-rate minister (平庸的) / his second-best suit / third-world people / In third-person narration / the third-largest car company (因為只有一家所以用 the) / a last-minute decision （best / largest 是可以當名詞使用的）
長短不加 ed => long-term memory (長期) / a long-range weather forecast / long-distance running / a short-term contract / a short-range radar / a short-distance ferryboat system
高低不加 ed => a high-quality product / a high-speed space shuttle / a high-tech job / a low-income family / a low-risk way.
full 不加 ed。=> a full-time (part-time) job / a full-length film / a full-scale analysis / a full-size image / （part- ＆ last- 開頭在 corpus 裡就只有 part-time）
Verb 基底：Adj/Adv/Noun + Verb-ing/-ed
Adj 開頭：a good-looking car / a easy-going girl / a ready-made product / a foul-smelling refrigerator
此用法是以形容詞修飾動詞，然後再去修飾名詞。其本體是接形容詞的動作 (Linking Verb)，此外，請注意這種動作只有主動用法。例如：a good-looking person = a person who looks good。
Adv 開頭：
主動 => a long-lasting ship / a tight-fitting pair of shoes / a quick-thinking kid / a fast-acting pain painkiller / a well-paying job / a free-thinking pioneer / a left-leaning politician
被動 => a well-developed game / a fully-trained police officer / a brightly-lit room / a well-known teacher / a highly-respected woman / a densely-populated zone / a long-forgotten story / a long-standing concern / a long-awaited novel
此用法以副詞修飾動作，然後再去修飾名詞。其本體是正常的動詞用法，分主被動。例如：a well-paying job = a job which pays well. （主動）；a well-developed game = a game that is developed well. （被動）
「tight / long / short / quick / fast / free / left」的形容詞與副詞都長的一樣。其中 free 和 freely 的差異在於，freely 是外在動做上的自由，而 free 當副詞時則是抽像的自由。 quickly 也是強調外在的動做，quick 則描述本質上的速度感。
a long-lasting ship 原句是 a ship that last long，為主動用法，所以 Verb-ing。a long-awaited novel 原句則是 a novel that is awaited long，為被動用法，所以 Verb-ed。
Noun 開頭：
主動 => an award-winning movie / mouth-watering food / record-breaking rain / time-saving service / an English-speaking country / a fun-loving person / a mind-altering experience / a soul-sucking job / a life-changing lesson / a heart-pounding moment
被動 => a wind-powered planet / a sun-dried fruit / a water-cooled system / a money-related issue / a self-created problem / a steel-reinforced wall
其他（無法歸納的用法，歡迎指教！）
- a short-lived worm / a long-lived kingdom => 筆者猜測，應該是屬於「名詞」基底的用法，然後把 life 變形成 lived （然而，long / short + noun 理論上不用加 ed，這邊卻要，所以筆者無法歸納其用法）
- a laid-back teacher