'thick-lipped' originates from the combination of 'thick' and 'lip,' where 'thick' meant 'having a large distance between sides' and 'lip' referred to the fleshy part around the mouth.

'Thick-lipped' was formed by combining the words 'thick' and 'lip' in English, maintaining its descriptive nature over time.

Initially, it meant 'having full lips,' and this meaning has remained consistent in modern usage.