AnalyzerSentence analysis2SpansSentence空しい努力1000 character limitAnalyzeSentence空むなしい努ど力りょくSpan Details空むなしいempty; void; hollow; vain; futile; fruitless; lifeless; empty of life-> 虚しいi-adjective努ど力りょくeffort; hard work; endeavornoun, suru verb