Plenty of synonyms/hyponyms that can be used in place of 차:
- 냉차: cold tea
- 녹차: green tea
- 홍차: black tea (홍 is actually red)
- 차량: vehicle; carriage; traffic
- 자동차: automobile/car
- 승용차: passenger car
- 경찰차: police car
- 자가용: one’s own [personal] car
Usually, people don’t use nouns in isolation anyway. A minimum amount of context will be enough to disambiguate or at least narrow the probability of one meaning over the other:
- 차 좀 더 드시겠어요? (Would you like some more 차?)
- 차를 마시다 (to drink 차)
- 차 한 잔 (a cup of 차)
- 커피와 차 (coffee and 차)
- 차 on a restaurant menu
- 차에서 내리다 (to get out of the 차)
- 차를 운전하다 (to drive a 차)
- 차 앞에 (in front of the 차)
- 차는 경찰이 (차 … police)
Fun fact: With only a few exceptions, there are only two ways of saying "tea" in the diverse languages of the world - either "tea" or "cha". Because trade routes. https://qz.com/1176962/map-how-the-word-tea-spread-over-land-and-sea-to-conquer-the-world/
In a nutshell, both words are borrowed from Chinese, and the Chinese words sound somewhat similar, so the Korean pronunciations converged. In fact, 차 is the Korean pronunciation of a huge number of Chinese symbols! A lot of Korean vocabulary is borrowed from Chinese, which is cool because most of these words also got borrowed into Japanese. The problem being, all modern Chinese languages, as well as the variety of Chinese where most of these loanwords came from, are tonal languages, meaning some words are different from each other only in the pitch of the speaker's voice as they're said. For example, 馬 is pronounced mǎ in Mandarin, with the voice starting middle pitch and dropping low before immediately rising up high at the end, while 媽 is pronounced mā, with the voice staying somewhat high in the register and at the same point for the duration of the word. Korean is non-tonal, so when these words get borrowed in they end up sounding the same.
The 차 in 자동차 is the Korean reading of the hanja 車 (Mandarin pinyin: chē), which means "vehicle" (the whole word is borrowed from the Chinese 自動車 (pinyin: zìdòngchē), meaning "self-moving vehicle"). The vowel and tone combination in the original Chinese is basically impossible to directly import to Korean (the "e" in this syllable is used for a sound something like the 'e' in "other"), so we wound up with 차 "cha"; similarly, the Japanese read this kanji as しゃ "sha".
차 for "tea", meanwhile, comes from the Chinese 茶 (pinyin: chá); the Korean reading of this hanja is much closer to the Chinese word, but is also unfortunately pronounced exactly the same as a number of other hanja with similar-sounding Chinese origins. The Japanese, by the way, pronounce this word as ちゃ "cha".
Cross-posting from another thread (차 and 자동차):
Interestingly, they were different sounds at some point. I’m not sure whether any dialect makes the distinction today, but the North Korean scholars prescribed spelling rules that would have spelt a lot of contemporary homonyms differently had they gone through.
Based on Chinese rime information and the recommendations provided, I’d say these would be the hypothetical spellings—at least in the north:
- 茶: 차 (← Middle Korean 따)
- 車: 챠 (← Middle Korean 챠)
Of course, just like in South Korea, spelling reforms hit a snag. Politics destroyed the whole spelling reform thing.
As the hypothetical Middle Chinese pronunciations for 茶 and 車 were respectively /ɖˠa/ and /t͡ɕʰia/, it’s not surprising that the borrowings differ in pronunciation in at least some sinoxenic borrowings (Japanese ちゃ v. しゃ). In Korean—as in other languages—the differing sounds continued to evolve (e.g.: 듕귁 → 중국; ᄍᆞ → 자; ᄇᆡᆨ〮 → 백) after borrowing and some became identical. Middle Chinese also evolved to Mandarin in parallel to that process, so the modern pronunciations do not actually reflect on each other.
Surprisingly, the invention of 한글 came with a prescription for spelling Chinese sounds which the Koreans could not pronounce faithfully anyway—much like the silent letters in French words like doigt. So the “accurate” spellings were soon ignored and the resulting borrowings were spelt as they sounded. This meant that a large number of 漢字 would end up being spelt the same way.
Why would English speakers be confused that two different words can have the same spelling and pronunciation? English has a plethora of such words. To tell a lie. To lie down. To strike a match. To match things up. To go to a match. Go to a boxing ring, wearing a ring on your finger, while you ring up an order.
You'll just have to use context to decide. If there's no context, pick one and pray.