赛车(sài chē) - car racing, motor racing in Mandarin

赛车 (sài chē) covers both car racing as a sport and, in context, a racing car itself, from 赛 (sài, to compete, a race or competition) and 车 (chē, vehicle). The same 赛 (sài) turns up in 比赛 (bǐ sài), match or competition, so 赛车 (sài chē) reads literally as "competition vehicle" or "vehicle competition" depending which side of the compound you lean on.

Add 手 (shǒu, hand, here "person who does X") and you get 赛车手 (sài chē shǒu), racing driver, the same pattern that builds 歌手 (gē shǒu), singer, and 选手 (xuǎn shǒu), contestant.

AQA's "car racing" gloss points at the sport sense, but a Mandarin speaker hearing 赛车 (sài chē) on its own will often picture the vehicle rather than the activity, so lean on context, 比赛 (bǐ sài) or 手 (shǒu), to make the sense clear.