yearful adjective 1noun 1forms 4 adjective1 •(rare) Full of years; elderly; aged.[…] but into the quiet haunts of the yearful ones ye cannot as yet hope for admission. — 1907 noun1 •The amount that occurs in a year; a year's worth (of something).He had three yearsful of news to relate and in it all not a word of discouragement, but enthusiasm for what has already been done and plans for what is yet to be done. — 1904 formsyearfuls · yearsful · more yearful · most yearful