Vow to ignore men in suits? (5)

I believe the answer is:

swear

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'vow' is the definition.
(I know that swear is a type of vow)

I don't understand the rest of the clue.

(Other definitions for swear that I've seen before include "Asseverate" , "Assert" , "Affirm" , "Express annoyance" , "Avow" .)

I've seen this clue in The Sun.

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