word-forming factor meaning "state or condition of being," from Old English -had "problem, place," cognate with German -heit, Dutch -heid, all from Proto-Germanic *haidus "manner, quality," actually "bright look," from PIE (s)kai- (1) "bright, shining." Originally a free-standing term (see hade); in Modern English it survives only within suffix.
A termination denoting condition, problem, high quality, personality, totality, as in manhood, childhood, knighthood, brotherhood. Sometimes its written, mainly in obsolete terms, when you look at the form -head.
A termination denoting state, condition, quality, character, totality, as in manhood, childhood, knighthood, brotherhood. Frequently it's written, mainly in obsolete words, in the form -head.