rationalize
/ˈræʃənəˌlaɪz/
verb
also Brit rationalise -izes; -ized; -izing
to think about or describe something (such as bad behavior) in a way that explains it and makes it seem proper, more attractive, etc. [+ obj]
[+ obj] chiefly Brit :to find ways to make (something, such as an industry, a company, etc.) waste less time, effort, and money