龌 and 龊 are both phono-semantic characters. They share the same semantic component 齿. What does 龌龊 mean？
齿 tooth+ 屋 house = 龌 wò narrow, small, dirty
齿 tooth + 足 foot = 龊 chuò narrow, small, dirty
龌龊 is a binding word.
龌龊 is used to mean:
1. filthy, dirty
2. despicable. mean
3. Narrow minded, confined to small matter
As you can see all the meanings of 龌龊 are negative and it is therefore a derogratory word. 龌龊 is usually used to describe a person, place or something.
For example:
That man is so despicable and I don’t want to see him again. 那个男人真龌龊，我再也不想见到他。
Tom had never seen a dirtier or more miserable place. 汤姆从来没有见过这么我错的地方。
Who knows all the dirty secrets around here? 谁知道这里所有龌龊的秘密？
龌龊 expresses very strong emotion of “dislike”, so make sure you want to use this word to express a derogatory meaning, otherwise, just avoid using it.