stray

Compared meaning: not in the place it should be (adjective).

比较义项：不在原本该有的位置——丢失、下落不明或无主流浪（形容词）。

• lost

  Describes a possession the owner once had but no longer has; used informally for personal belongings like keys, wallets or phones the owner is trying to recover.

  指某物本来属于某人，但现在已经不再拥有；常用于口语中描述个人物品（如钥匙、钱包、手机），主人正设法找回。

  He finally found his lost keys under the couch after searching all morning.

  他找了一上午，终于在沙发底下找到了自己丢失的钥匙。

• missing

  A more neutral, often official term for a person or thing whose current location is unknown; common in reports and searches, without stating whose fault it is.

  语气更中性，常用于正式场合，指人或物目前下落不明；常见于报告或搜寻场景，并不说明是谁的责任。

  Officials released a photo of the missing child to help the search efforts.

  官方公布了这名失踪儿童的照片，以协助搜寻工作。

• stray 本词

  Used almost only for animals with no owner or home, wandering on their own; unlike lost, it does not imply the animal ever belonged to someone.

  几乎只用来形容无主、四处游荡的动物；和lost不同，它并不暗示这只动物曾经属于某人。

  A stray dog followed us home from the park and now lives in our yard.

  一只流浪狗从公园跟着我们回家，现在就住在我们院子里。

All three describe something not in its proper place. Lost implies it was once owned. Missing is neutral, used in official searches. Stray describes only ownerless animals wandering freely. Lost also means unable to find your way; stray also means random. Not compared here.

这三个词都表示某物或某人“不在该在的地方”，但语气和搭配不同：lost强调本来拥有、后来失去；missing更中性、常用于正式的寻人寻物场合；stray几乎只用于无主、四处游荡的动物。这里不比较lost另一常见的“迷路的”义项（如I got lost），也不比较stray“偏离主题的、偶然的”义项（如a stray remark）。

Compared meaning: happening now and then, not regularly (adjective).

比较义项：偶尔发生、不规律或偶然出现的（形容词）。

• occasional

  Describes something pleasant or neutral that happens now and then, at scattered but unremarkable times; almost always used before a noun (an occasional treat), never as a predicate like 'became occasional'.

  表示某种令人愉悦或中性的事情偶尔发生、间隔不固定；几乎总是放在名词前作定语（an occasional treat），不能像 irregular 那样直接作谓语（不说 became occasional）。

  He treats himself to an occasional slice of chocolate cake.

  他偶尔会犒劳自己吃一块巧克力蛋糕。

• irregular

  Focuses on an unsteady rhythm or timing rather than simple infrequency; can describe something happening often but unevenly, and unlike the others can stand alone as a predicate (his heartbeat was irregular).

  强调节律或时间安排不稳定，而不只是“不常发生”；可以描述频繁但不均匀的情况，并且和其他几个词不同，可以单独作谓语（his heartbeat was irregular，心跳不规律）。

  Her sleep schedule became irregular after she started the night shift job.

  她开始上夜班后，睡眠安排变得不规律了。

• stray 本词

  Describes one isolated occurrence that happens purely by chance and stands apart from any pattern; typically modifies a single physical object, remark or thought rather than describing frequency.

  指单一的、纯属偶然、脱离任何规律的个例；通常修饰单个具体的事物、话语或念头，而不是用来描述发生的频率。

  A stray bullet shattered the window during the late-night celebration.

  深夜庆祝活动期间，一颗偶然飞来的子弹打碎了窗户。

• sporadic

  Emphasizes isolated bursts of activity that surface now and then over a stretch of time, often with a mildly negative or noteworthy tone, and typically describes an ongoing situation rather than one single object.

  强调在一段时间里断断续续地爆发或出现，常带一点负面或值得关注的语气，通常描述持续存在的状况，而不是单一的一件事物。

  Sporadic fighting broke out along the border throughout the ceasefire.

  在停火期间，边境沿线断断续续地爆发了零星的战斗。

All four mean something happens now and then, not regularly. Occasional is neutral, mostly before a noun. Irregular stresses unsteady timing. Sporadic stresses bursts of activity, often negative in tone. Stray means one chance occurrence, not a frequency. Irregular's and stray's other senses: not compared.

这四个词都能表示“不经常、非固定规律地发生”，但语气和用法不同：occasional 语气中性，偏日常，几乎只作定语；irregular 强调节律或时间安排不稳定，可以单独作谓语；sporadic 强调断断续续、一阵一阵地出现，常带一点负面语气；stray 指单一的、纯属偶然的个例，通常修饰具体事物而非描述频率。这里不比较 irregular“形状不规则的”和 stray“走失的、流浪的（动物）”等其他含义。