三个单词均有克制和约束的含义。abstain主要是指自我约束以放弃某项权利或戒除某项行为，尤指不当或不健康的行为[1]。refrain多指暂时或短时间的一种克制或约束行为或克制冲动[2]。forbear则常指出于忍耐或慈善而实施的自我克制行为[3]。

[1 ] "To hold oneself back voluntarily, especially from something regarded as improper or unhealthy. ” Cf. James E. Clapp, Random House Websters Dictionary of the Law，at p. 4, Random House (2000).
[2] "Refrain has to do with withholding an action temporarily, or checking a momentary desire. ” Cf, The Editors of the Readers Digest, Use the Right Word, at p. 2, The Reader's Digest Association Proprietary Ltd. (1971).
[3]“Forbear is, in its intransitive sense, to exercise self-control, often out of motive of patience, or charity. ” Id. at p. 2.