Merriam-Webster's Word of the Day for February 04, 2012 is:

lymphatic • \lim-FAT-ik\  • adjective
1 a : of, relating to, or produced by lymph, lymphoid tissue, or lymphocytes b : conveying lymph 2 : lacking physical or mental energy : sluggish

Examples:
Because of the snowstorm, the day was a lazy one and the whole family felt lymphatic.

"Tonsils are collections of lymphatic tissue on both sides of the back of the mouth." -- From an article by Dr. Rhonda Patt in the Charlotte Observer (North Carolina), January 3, 2012

Did you know?
Lymph is a pale liquid in the body that helps maintain fluid balance and removes bacteria from tissues. Today, we understand that lymph plays an important role in the body's immune system. In the past, however, it was commonly believed that an excess of lymph caused sluggishness -- hence the "sluggish" meaning of "lymphatic." The word "lymph" comes from Latin "lympha" ("water" or "water goddess"), which itself may be a modification of the Greek word "nymphē," meaning "nymph." Both "lymph" and its related adjective "lymphatic" have been used in English since the mid-17th century.