Here are some examples:
Adjective:
* "The sky is cloudy." (Describing the sky)
* "We had a cloudy day at the beach." (Describing the day)
Adverb:
* "The water was cloudy with sediment." (Describing how cloudy the water was)
* "The room was cloudy with smoke." (Describing how cloudy the room was)
To determine the part of speech, consider its function in the sentence. If it describes a noun (the sky, the day), it's an adjective. If it describes a verb (was, was) or another adjective (cloudy), it's an adverb.