Verb
go off on a tangent (third-person singular simple present goes off on a tangent, present participle going off on a tangent, simple past went off on a tangent, past participle gone off on a tangent)
(US) Synonym of fly off at a tangent
Halfway through any work, one is often tempted to go off on a tangent. Once you have yielded, you will be tempted to yield again and again... Finally, you would only produce something hybrid. Barbara Hepworth