The most common and most likely answer to this crossword clue is the 8 letter word TUBERCLE
I've seen this crossword clue in Independent
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More clues leading to the result TUBERCLE
Buddy explains!
The straight part
We know that "Bump" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case bump = tubercle.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 TUBERCLE mean?
TUBERCLE noun- A round nodule, small eminence, or warty outgrowth, especially those found on bones for the attachment of a muscle or ligament or small elevations on the surface of a tooth.
- A small rounded wartlike protuberance of the roots of some leguminous plants; the lip of certain orchids, cacti.
- A small rounded nodule forming the characteristic lesion of tuberculosis.