Cool, Cold To The Touch
い adjective
つめたい
冷たいコーヒーのことを、日本語では「アイスコーヒー」と呼びます。
We call cold coffee "ice coffee" in Japanese.
Something that is cool is cold. This refers to something that is cold to the touch, not the weather or something like that (which is 寒い).
Since this word consists of a kanji with hiragana attached, you can bet that it will use the kun'yomi reading. You didn't learn that reading with this kanji, so here's mnemonic to help you: Something that is really cold to the touch is cold enough to make ice cream with.