Under the sway of arbitrary opinions
Undertaken under propitious circumstances [propitious = auspicious, favorable; kindly]
Uneasy sense of impending change
Unequaled simplicity and directness of purpose
Unexceptional in point of breeding
Unexpected obstacles and inextricable difficulties
Unfailing and miraculous foresight
Unfeigned astonishment and indignation
Unfounded and incredible calumnies [calumnies = maliciously false statements]
Unhampered by binding alliances