Something is warm if it isn't too hot and it isn't cold either. The cat in the picture is warm and snug in the man's jacket.
Something is waterproof if water cannot pass through it or soak into it. The raincoat in the picture is waterproof.
Something is watertight if it can hold a liquid like water without losing any of it. Common things that are watertight include boats, buckets, cups and bottles.
Weak means that something or someone is lacking strength, health, or energy/a>. If you're sick, you might feel weak.
Something is weathered if it has been damaged by long-term exposure to the weather.
Something is wet if it is covered with a liquid, like water. When you come out of a shower or bath or if you get caught in the rain, you are wet. If you are very, very wet, you are soaked. The opposite of wet is dry.