The most common and most likely answer to this crossword clue is the 6 letter word WARPED
I've seen this crossword clue in The Guardian
W
A
R
P
E
D
Buddy explains!

The straight part
We know that "Out-of-shape" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case out-of-shape = warped.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 WARPED mean?
WARPED verb- To twist or become twisted, physically or mentally:
- (ropemaking) To run (yarn) off the reel into hauls to be tarred.
- To arrange (strands of thread, etc) so that they run lengthwise in weaving.
- To plot; to fabricate or weave (a plot or scheme).
- To change or fix (make fixed, for example by freezing).
- To move:
- (obsolete outside dialectal, of an animal) To bring forth (young) prematurely.
- To fertilize (low-lying land) by letting the tide, a river, or other water in upon it to deposit silt and alluvial matter.
- (very rare) To throw.
- Distorted by warping; twisted out of shape
- Of a person's mind, attitudes, etc, perverse, strange, aberrant or deviant.