late 14c., "unfortunately, unluckily;" early 15c., "wretchedly, without happiness," from un- (i) "not" + happily, or from unhappy + -ly (2.). Similar formation in Old Norse unheppiliga.
they were unhappily married
unguided
ungulate
unhallowed
unhampered
unhand
unhappily
unhappiness
unhappy
unharmed
unharness
unhealthy