The most common and most likely answer to this crossword clue is the 13 letter word HYPOCHONDRIAC
I've seen this crossword clue in The Times
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More clues leading to the result HYPOCHONDRIAC
Buddy explains!
The straight part
We know that "One lacking complaint nevertheless inclined to be patient" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case one lacking complaint nevertheless inclined to be patient = hypochondriac.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does HYPOCHONDRIAC mean?
HYPOCHONDRIAC noun- A person affected with hypochondria.
- Related to, or affected by hypochondria
- Related to, or located in the hypochondrium.