If someone explains away a mistake or a bad situation they are responsible for, they try to indicate that it is unimportant or that it is not really their fault.
He evaded her questions about the war and tried to explain away the atrocities. [VERBPARTICLE noun]
I had noticed blood on my husband's clothing but he explained it away. [VERB noun PARTICLE]
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explain away in British English
verb
(tr, adverb)
to offer excuses or reasons for (bad conduct, mistakes, etc)
explain away in American English
to state reasons for so as to justify, often by minimizing, or make understandable
See full dictionary entry for explain
Examples of 'explain away' in a sentence
explain away
He has lied to try and explain away his barbaric crime.
Times, Sunday Times (2013)
And when the courageous stands you do take are explained away as the result of parental pressure, there's scant incentive to remain upright.