'未甚' is an adverbial phrase meaning 'not yet to a great degree' or 'not particularly/strongly yet.' It combines the character 未 (wèi), meaning 'not yet' or 'has not,' with 甚 (shèn), meaning 'very,' 'extremely,' or 'to a great extent.' Together, they express a moderate or incipient state — something exists or occurs, but only weakly, mildly, or incompletely. It often appears in formal, literary, or medical contexts, especially when describing symptoms, conditions, or developments that are present but still mild.

This phrase carries a restrained, objective tone and is common in written Chinese — such as clinical notes, academic reports, or classical-style prose — rather than casual speech. It functions similarly to 'not markedly' or 'not notably' in English medical writing. Because it’s two characters working as a fixed unit, it usually modifies verbs or adjectives directly and rarely stands alone.