perfectly

Perfectly is an English adverb formed from the adjective perfect plus the adverbial suffix -ly. It has several closely related senses. It can describe something that is without flaws or error, as in the phrase the machine works perfectly. It can express a high degree or exactness, as in perfectly accurate or perfectly balanced. It can also function as an intensifier meaning completely or to a great extent, often before adjectives or adverbs, as in perfectly reasonable, perfectly well, or perfectly timed. The adverb is versatile across formal and informal registers, though some contexts favor milder synonyms such as very or completely.

Etymology: The word derives from the Middle English period, from the adjective perfect, which itself comes from Old French parfait and ultimately from Latin perfectus, meaning completed or finished.

Usage notes: Perfectly typically modifies verbs (works perfectly), adjectives (fine, clear), or other adverbs (completely, entirely). In formal writing, it is common and uncontroversial when describing non-judgmental states or measurements; in conversational English, it can carry an ironic or emphatic nuance. Some contexts call for hedging; for example, perfectly okay might be used more cautiously than perfectly acceptable. Related terms include perfection and expressions such as perfectly timed, which reflect the same sense of thorough completeness.