The word 'youngish' is a straightforward modern English formation, combining the native Germanic adjective 'young' with the equally ancient suffix '-ish'. The root 'young' descends from Proto-Germanic jungaz, itself from the Proto-Indo-European root yeu- meaning 'vital force, youthful vigor'. The suffix '-ish' originates from the Proto-Germanic -iskaz, used to form adjectives of origin or characteristic. The semantic logic is transparent: by attaching '-ish' to 'young', the word creates a diminutive or moderating sense, shifting from the absolute state of being young to the relative quality of being somewhat or tending toward young. This pattern is highly productive in English, allowing for the creation of informal adjectives that convey approximation.

Structure: young (having lived for a short time) + ish (having the quality of; somewhat) - young: From Old English geong, of Germanic origin; related to Dutch jong and German jung. Functions as the core adjective root. - ish: From Old English -isc, of Germanic origin; originally an adjective-forming suffix meaning 'of the nature of' or 'belonging to'. In modern English, it often forms adjectives meaning 'somewhat' or 'approximately'.