How to say "strictly" in Japanese

• 厳にげんにCommon
  adverbThe common choice for the plain sense of 'strictly': handling someone or something severely and with stern discipline, as when a teacher or boss enforces rules firmly.
  ここではたばこを吸すうことを厳げんに禁きんじられている。↗

  Smoking is strictly forbidden here.
• みっしり
  adverb (with と)A mimetic word whose core image is tightness — things packed or fitted closely together. Though it can be glossed 'strictly; severely', it is seldom the word you want: it really describes dense, tight packing.
• みっちり
  adverb (with と)Covers 'strictly' in the sense of rigorously and intensively: being drilled or trained hard, with no let-up. Fits thorough, unrelenting instruction or practice.
• 厳としてげんとして
  expression, adverbLess common; it paints a stern, unbending, authoritative attitude rather than everyday strictness — a stance or rule maintained resolutely and without compromise.

Choose 「厳に」 for the general sense of sternly enforcing rules or discipline; 「みっちり」 for rigorous, intensive training; 「厳として」 for a stern, authoritative stance; 「みっしり」 really describes tight packing and seldom means 'strictly'.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

• 厳にげんにstrictly
• みっしりstrictly
• みっちりintensely
• 厳としてげんとしてresolutely