Fíftíne-wintre

According to the Old English Dictionary:

fíftíne-wintre

adj. Fifteen years old:--Ðá hé wæs fífténewintre, Bl. H. 213, 1. Ꝥ man nǽnne gingran mann ne slóge þonne xv-wintre man, Ll. Th. i. 240, 28. fiftine-wintre