Failing to observe something; unobservant.(adjective)
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Use "unobserving" in a sentence
"Filled with dreary imaginations, I passed through many beautiful and majestic scenes; but my eyes were fixed and unobserving."
"To an eye so unobserving as that of Bucklaw, her demeanour had little more of reluctance than might suit the character of a bashful young lady, who, however, he could not disguise from himself, was complying with the choice of her friends rather than exercising any personal predilection in his favour."
"These, when observing men have made them, unobserving men, when they are proposed to them, cannot refuse their assent to."