The most common and most likely answer to this crossword clue is the 7 letter word STEP-UP
I've seen this crossword clue in Financial Times
S
T
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P
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More clues leading to the result STEP-UP
Buddy explains!
The straight part
We know that "volunteer" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case volunteer = step-up.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 STEP-UP mean?
STEP-UP noun- (exercise) A workout movement wherein one leg stands on an elevated surface and lifts in the concentric part the rest of the body up onto it to target – depending on angle and starting distance of the other leg and weights applied by the arms – the femoral and gluteal muscles variously.
- That increases in stages.
- (of a transformer etc) That increases a voltage.