How to say "penetration" in Japanese

• 突破とっぱJLPT N1approx.Common
  noun, suru verb, transitive verbPenetration as forceful breakthrough: pushing through a defensive line, barrier, or obstacle until it gives way. It emphasizes the moment of breaking through rather than gradual entry or soaking in.
• 透過とうかCommon
  na-adjective, noun, suru verb, intransitive verbPenetration in the physical sense: light, rays, or other energy passing through a material, as when glass transmits light. It is about transmission, not forceful entry or gradual spread.
• つっこみCommon
  nounA thrust or charge — the act of plunging or driving in. It only occasionally corresponds to 'penetration'; for most senses of the English word this is seldom the term you want.
• 侵入しんにゅうJLPT N2approx.Common
  noun, suru verb, intransitive verbPenetration as hostile entry: an incursion into territory, a raid, or intruders getting inside. The emphasis is on the act of entering, not on pushing through a barrier or permeating.
  「ピッキングの道具どうぐ無なしで、どうやって侵入しんにゅうした？」「トイレの窓まどがあいた」↗

  "With no picks how did you break in?" "The toilet window was open."
• 浸透しんとうCommon
  noun, suru verb, intransitive verbPenetration in the figurative sense: ideas, culture, or influence gradually permeating, and a product or company penetrating a market. The motion is slow soaking-in and spread, not a single forceful push.
  日本にっぽんからの輸入ゆにゅう製品せいひんがアメリカの消費者しょうひしゃ市場しじょうに浸透しんとうするには長ながい時間じかんがかかった。↗

  It took a long time for Japanese imports to penetrate the American consumer markets.

Choose by what is doing the penetrating: forceful breakthrough of a barrier (突破), physical transmission through matter (透過), a thrust or charge (「つっこみ」), hostile entry into territory (侵入), and gradual permeation of ideas or markets (浸透).

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

• 突破とっぱbreaking through
• 透過とうかpenetration
• つっこみthrust
• 侵入しんにゅうinvasion
• 浸透しんとうpermeation (of thought, ideology, culture, etc.)
• 貫入かんにゅうpenetration
• 穿通せんつうpenetration
• 透りとおりpenetration (as of light)
• 挿送そうそうpenetration
• 明察めいさつdiscernment
• 溶け込みとけこみintegration (e.g. social)
• 卓識たくしきclearsightedness
• 観入かんにゅうinsight
• 卓見たっけんexcellent idea
• 挿入そうにゅうinsertion
• 突貫とっかんpenetration
• 貫徹かんてつpenetration
• 眼光がんこうinsight
• 本チャンほんチャンactual sexual intercourse (i.e. not simulated)