The most common and most likely answer to this crossword clue is the 5 letter word FEMUR
I've seen this crossword clue in Independent
F
E
M
U
R
More clues leading to the result FEMUR
- Father eating bird finds bone
- Bone from female bird, rook
- Iron Man’s first, original 16 component
- Tips of feather spanning bird’s bone
- What’s inside leg measurement – perhaps moleskin trousers?
- Father describing flightless bird’s bone
- “Bone” is “bird” in French
- Part of leg iron? Flipping odd!
- Bone from big bird found in middle of seafront
- Part of frame Duke removed from fine object
Buddy explains!

The straight part
We know that "Bit of leg shown by half-cut fems with revolutionary spirit (5)/Bit of leg" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case bit of leg shown by half-cut fems with revolutionary spirit (5)/bit of leg = femur.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 FEMUR mean?
FEMUR noun- A thighbone.
- The middle segment of the leg of an insect, between the trochanter and the tibia.
- A segment of the leg of an arachnid.