The most common and most likely answer to this crossword clue is the 5 letter word BOLUS
B
O
L
U
S
More clues leading to the result BOLUS
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The straight part
We know that "soft lump" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case soft lump = bolus.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 BOLUS mean?
BOLUS noun- A round mass of something, especially of chewed food in the mouth or alimentary canal.
- A single, large dose of a drug, especially one in that form.
- To take a dose of insulin at a mealtime in order to control one's blood glucose level in diabetes.