Lightweight
Light, Light Weight
い adjective
This is a single kanji with an い on the end, meaning you know it's probably an adjective. What's the adjective form of lightweight? It's also lightweight.
かるい
The reading you learned with the kanji is the reading you'll be using here. Because of that, this word is kind of a lightweight.
このはこは、あのはこよりも軽い。
This box is lighter than that one.
この毛ぬき、びっくりするぐらい軽いんだけど。
This pair of tweezers is surprisingly light.
毎日軽い朝ごはんを食べる。
Every day I eat a light breakfast.