The sense seems to be that, owing to his position in the nation, the priest is not to defile himself in any cases except those named in Leviticus 21:2-3. The Septuagint appear to have followed a different reading of the text which would mean, “he shall not defile himself for a moment.” The explanation in the margin of our version is hardly in keeping with the prohibition to Ezekiel on a special occasion. See Ezekiel 24:16.
Related Commentaries of Leviticus 21:4
Leviticus 21:4
4 But he shall not defile himself, being a chief man among his people, to profane himself.