Free for Limerick - blame the lineman for this (5,5)

I believe the answer is:

blank verse

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This could be a double definition.

'free for limerick' is the first definition.
The definition and answer can be both related to communication as well as being singular nouns.
Maybe there's an association between them I don't understand?

'blame the lineman for this' is the second definition.
The definition suggests a singular noun which matches the answer.

Can you help me to learn more?

(Another definition for blank verse that I've seen is " Rhymeless poetry".)

I've seen this clue in the Irish Times and the Irish Times (Crosaire).

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