Denshi Jisho — Online Japanese dictionary

勝る まさる 1: to excel; to surpass; to exceed; to have an edge; to be superior; to outrival;
2: to outweigh; to preponderate
Common word, Godan verb with ru ending, Intransitive verb 
勝るとも劣らぬ まさるともおとらぬ not at all inferior to; rival or surpass; compare favorably (with)
Noun 
勝るとも劣らない まさるともおとらない not at all inferior to; rival or surpass; compare favorably (with)
Adjective 

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