unlikely

Compared meaning: not likely to happen or be true (adjective).

比较义项：不太可能发生或不太可能是真的（形容词）。

• unlikely 本词

  The common, neutral word for low probability, used constantly in everyday speech and writing; pairs naturally with 'that' clauses and modifiers like 'highly' or 'very'.

  这是表示可能性低的常用中性词，在日常口语和书面语中都极为常见；常与that从句连用，也常与highly、very等修饰词搭配。

  It's unlikely she'll call back tonight, so don't wait up.

  她今晚不太可能回电话，所以不用熬夜等了。

• improbable

  A more formal, bookish word suggesting a reasoned or statistical judgment about low probability; sounds stiff or overly analytical in casual conversation.

  这是一个更正式、更书面化的词，带有经过推理或统计判断得出可能性很低的意味；在日常口语中使用会显得生硬或过于分析化。

  The detective called the suspect's alibi highly improbable given the evidence.

  根据这些证据，侦探认为嫌疑人的不在场证明极不可能属实。

Unlikely and improbable both mean something has low probability. Unlikely is the common, neutral word, used constantly in speech and writing, often with 'that' clauses. Improbable is more formal and bookish, suggesting a reasoned judgment, and sounds stiff in casual conversation.

这两个词都表示某事发生或成立的可能性很低，语气都比较温和、客观，常用于陈述判断而非强烈断定。unlikely 是日常口语和书面语都常用的中性词；improbable 更书面、正式，带一点理性推断或概率评估的意味，日常口语中较少使用。