Unfortunately a lower bunk is impractical (10)

I believe the answer is:

unworkable

'impractical' is the definition.
(I've seen this before)

'unfortunately a lower bunk' is the wordplay.
'unfortunately' indicates an anagram (a bad or unfortunate spelling).
'a'+'lower'+'bunk'='alowerbunk'
'alowerbunk' with letters rearranged gives 'UNWORKABLE'.

'is' is the link.

(Another definition for unworkable that I've seen is " impractical".)

I've seen this clue in the Sydney Morning Herald.

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