princeling (n.)

c. 1200, "governor, overseer, magistrate; leader; great man, chief; preeminent representative of a group or class" (mid-12c. as a surname), from Old French prince "prince, noble lord" (12c.), from Latin princeps (genitive principis) "first person, chief leader; ruler, sovereign," noun use of adjective meaning "that takes first," from primus "first" (see prime (adj.)) + root of capere "to take" (from PIE root *kap- "to grasp").

German cognate Fürst, from Old High German furist "first," is apparently an imitation of the Latin formation.

As "heir apparent to a throne," mid-14c. (Prince of Wales). The meaning "king's son, scion of a royal family" is by mid-15c. From c. 1600 as a courtesy title given to non-regnant members of royal families, often confined to the younger sons of sovereigns. Prince Regent was the title of George, Prince of Wales (later George IV) during the mental incapacity of George III (1811-1820).

By mid-14c. prince was used as the type of a handsome, worthy, wealthy, or proud man. The modern colloquial meaning "admirable or generous person" is from 1911, American English.

diminutive word-forming element, early 14c., from Old English -ling a nominal suffix (not originally diminutive), from Proto-Germanic *-linga-; attested in historical Germanic languages as a simple suffix, but probably representing a fusion of two suffixes: 1. that represented by English -el (1), as in thimble, handle; and 2. -ing, suffix indicating "person or thing of a specific kind or origin;" in masculine nouns also "son of" (as in farthing, atheling, Old English horing "adulterer, fornicator"), from PIE *-(i)ko- (see -ic).

Both these suffixes had occasional diminutive force, but this was only slightly evident in Old English -ling and its equivalents in Germanic languages except Norse, where it commonly was used as a diminutive suffix, especially in words designating the young of animals (such as gæslingr "gosling"). Thus it is possible that the diminutive use that developed in Middle English is from Old Norse.