The word 'yellowish' is a straightforward English compound formed by adding the native suffix '-ish' to the colour term 'yellow'. The root 'yellow' descends from the Proto-Germanic 'gelwaz', itself derived from the Proto-Indo-European root 'ghel-', meaning "to shine", a root that also gave rise to words for gold, bile, and other bright or yellow substances. The suffix '-ish', with its ancient Germanic origins, is highly productive in English for creating adjectives that indicate approximation or resemblance. Therefore, the literal construction "yellow-like" logically evolved into the modern descriptive meaning of "slightly yellow".

Structure: yellow (colour) + ish (adjective suffix) - yellow: From Old English 'geolu', of Germanic origin, related to 'gold'. Functions as the base adjective denoting the colour. - ish: From Old English '-isc', a Germanic suffix forming adjectives. In this context, it means "having the quality to some degree" or "somewhat like".