Using a Thesaurus 類義語時点の使い方
"That's cool." He said this as the car revved its engines.
彼が車のエンジンを転回しながら、「かっこいいね」と呟きました。 The word "cool" is by most accounts, overused.
In a dictionary there a number of meanings of the word. Let's take a look at some of these.
英語の「cool かっこいい」はとても多く使われています。
辞書で調べると、いくつかの意味がでてきます。みてみましょう。
cool| kul | adjective 形容詞
1 「温度の低いもの」of or at a fairly low temperature: it'll be a cool afternoon | the wind kept them cool. • soothing or refreshing because of its low temperature: a cool drink in the leafy shade | figurative : the bathroom was all glass and cool, muted blues. • (especially of clothing) keeping one from becoming too hot: wear your cool, comfortable shirts.
2 「何かに対して暖かい気持ちまたは情熱を表現する」showing no friendliness toward a person or enthusiasm for an idea or project: he gave a cool reception to the suggestion for a research center. • free from excitement or anxiety: he prided himself on keeping a cool head | she seems cool, calm, and collected. • (of jazz, especially modern jazz) restrained and relaxed.
3 「魅力的、強い印象を与えるもの」informal fashionably attractive or impressive: I always wore sunglasses to look cool. • excellent: [as exclamation] : a computer you didn't even have to plug in. Cool! • used to express acceptance or agreement: if people want to freak out at our clubs, that's cool.
noun 名詞
1 「すずしい、天気など」(the cool) a fairly low temperature: the cool of the night air. • a time or place at which the temperature is pleasantly low: the cool of the evening.
2 「落ち着くこと」calmness; composure: he recovered his cool and then started laughing at us.
3 「ファッションセンスが良い、スマート」the quality of being fashionably attractive or impressive: all the cool of high fashion.
verb 動詞
「何かを冷やす」become or cause to become less hot: [no object] : we dived into the river to cool off | [with object] : cool the pastry for five minutes | figurative : his feelings for her took a long time to cool. • become or cause to become calm or less excited: [no object] : after I'd cooled off, I realized I was being irrational | [with object] : George was trying to cool him down. • (cool down) recover from strenuous physical exertion by doing gentle stretches and exercises; warm down.
In this instance, we see that it fits with example 3. So what might have been a better word to use in this case?
今回の場合、例3に一番似ていれると考えてもよいでしょう。ですから、代わりに違う言葉を使えるででしょうか?

That were a Thesaurus comes in handy. Look up cool and we might see something like the following.
こういう時に、類義語時点が便利です。
5 informal
she thinks she's so cool: fashionable, in fashion, in vogue, voguish, (bang) up to date, up to the minute, modern, all the rage, modish, trendsetting, stylish, chic; sophisticated, cosmopolitan, elegant, stylish, smart, chic, glamorous, classy, high-class, high-toned; attractive, appealing, impressive;
Some of these are a bit excessive, so you need to be careful that you don't just choose the first option. "Chic, glamorous, classy, high-class, high-toned; attractive, and appealing," are all words I'd avoid in this instance, but "impressive" would work.
少し意味が強すぎる言葉も含まれているので、気をつけないといけません。いつも一番目の単語を選んではダメですね。今回の文章では、「Chic, glamorous, classy, high-class, high-toned; attractive, and appealing」は使わないと思います。でも、「impressive」でしたら使えそうですね!
"That's impressive." He said this as as the car revved its engines.