Mortally

Mortally is an adverb derived from the adjective mortal. It most commonly denotes something that leads to death or is capable of causing death, such as in the phrases “mortally wounded” or “mortally ill.” In this sense it is close to synonyms like fatally or lethally.

The word also appears as a literary or emphatic intensifier, meaning “to a deadly extent” or “extremely.” This usage is less common in contemporary everyday speech and can come across as archaic or stylistic. Phrases such as “mortally afraid” or “mortally surprised” are more likely to be found in historical, fantasy, or dramatic writing than in plain language.

Etymology traces mortally to the Latin mortalis “mortal,” via Old French mortel. The adverbial form with the suffix -ly is standard in English, and its core meaning remains tied to death or fatality.

In practice, mortally is most often encountered in medical or military contexts (e.g., “mortally wounded,” “mortally ill”). In other contexts, speakers may prefer synonyms such as fatally, deadly, or extremely, depending on the precise sense. As with many words built around death, the preferred usage can depend on tone, register, and audience. When advising on usage, consider whether a literal fatal sense is intended or if an elevated, literary emphasis is desired.