suffix, godan verb (-mu)
start to appear; show signs of
Verb-forming suffix attached to nouns. Indicates that something is beginning to emerge or become visible. Common in words like 芽ぐむ (to bud) and 涙ぐむ (to become tearful).
木々が芽ぐみ始めた。
The trees have started to bud.
Her eyes became tearful.