Definition:
: a person of a weak or sickly constitution; especially : one whose chief concern is his or her ill health
Example:
"At this pool … are a multitude of scorbuticks, hypochondriacks and other valetudinarians." — William Simpson, The History of Scarbrough-Spaw, 1679
About the Word:
At first glance, there is little need to add valetudinarian to the arsenal of words taking up valuable real estate in your brain. After all, the English language already has a number of fine ways to describe a sick person (invalid, patient, and whatever term you use to describe that child on the bus who keeps sneezing on you). However, valetudinarian has the additional meaning "one whose chief concern is his or her own health," which sets that word apart from the blameless invalid and patients.
