To deviate from something means to start doing something different or not planned, especially in a way that causes problems for others.
例句
They stopped you as soon as you deviated from the script...一旦你偏離了劇本的內容，他們就會喊停。He planned his schedule far in advance, and he didn't deviate from it...他提前很早就制訂出了自己的進度表，然后從未偏離過它。
英漢詞典釋義
vi.
偏離; 越軌
His statements sometimes deviated from the truth.他的陳述有時偏離事實。
英英詞典釋義
Noun
1. a person whose behavior deviates from what is acceptable especially in sexual behavior
Verb
1. be at variance with; be out of line with
2. turn aside; turn away from
3. cause to turn away from a previous or expected course;