There was some exchange of words between `Uthman ibn `Affan and Amir al-mu'minin when al-Mughirah ibn al-Akhnas (1) said to `Uthman that he would deal with Amir almu'minin on his behalf whereupon Amir al-mu'minin said to al-Mughirah:
O' son of the accursed and issueless, and of a tree which has neither root nor branch. Will you deal with me? By Allah, Allah will not grant victory to him whom you support, nor will he be able to stand up whom you raise.
Get away from us. Allah may keep you away from your purpose. Then do whatever you like. Allah may not have mercy on you if you have pity on me.
(1). al-Mughirah ibn al-Akhnas ath-Thaqafi was among the wellwishers of `Uthman ibn `Affan and the son of his paternal aunt. His brother Abu'l Hakam ibn al-Akhnas was killed at the hands of Amir al-mu'minin in the battle of Uhud, because of which he bore malice against Amir almu'minin. His father was one of those people who accepted Islam at the time of the fall of Mecca but retained heresy and hypocrisy in heart.
That is why Amir al-mu'minin called him accursed, and he called him issueless because he who has a son like al-Mughirah deserves to be called issueless.