So deeply affected by love as to be unable to act normally.(adjective)
Exhibiting a lover's yearning.(adjective)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Use "lovesick" in a sentence
"Some other translations, naturally, use the term lovesick instead."
"CD and heard what she described as "lovesick puppy music.""
"‘For the lovesick is no remedy and alike are the madman and he.’"