较坚强的

较艰苦的（tough的比较级）

a not given to gentleness or sentimentality

s very difficult; severely testing stamina or resolution

a physically toughened

s substantially made or constructed

s violent and lawless

s feeling physical discomfort or pain (`tough' is occasionally used colloquially for `bad')

a resistant to cutting or chewing

s unfortunate or hard to bear

s making great mental demands; hard to comprehend or solve or believe