Dispenses cash hidden by boatman (3)

I believe the answer is:

atm

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'dispenses cash' is the definition.
I can't tell whether this definition defines the answer.

'hidden by boatman' is the wordplay.
'hidden' indicates a hidden word.
'ATM' is hidden within 'by boatman'.

Can you help me to learn more?

I've seen this clue in The Irish Times.

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