Stephen Crabb MP is a British politician of the Conservative Party, serving as the Member of Parliament for Preseli Pembrokeshire since the 2005 general election. In 2016, Crabb was briefly Secretary of State for Work and Pensions.
He described her intervention as "humbug" and repeated the word again.
BBC political editor Laura Kuenssberg described scenes in Parliament as an "absolute bear pit".
Mr Johnson was repeatedly challenged over his use of the word "surrender" to describe legislation passed earlier this month which on 31 October.
Pointing to a plaque in The Chamber , commemorating Mrs Cox, who was murdered by a right-wing extremist, She Said : "We should not resort to using offensive, dangerous or inflammatory language for legislation that we do not like, and we stand here under The Shield of our departed friend with many of us in this place subject to death threats and abuse every single day. "
"They often quote his words 'Surrender Act', 'betrayal', 'traitor' and I for one am sick of it.
In response, Mr Johnson said: "I have to say, Mr Speaker, I've never heard such humbug in all My Life . "'A threat against my child'
Tracy Brabin, who was elected as MP for Batley and Spen after Ms Cox was murdered, also urged the Prime Minister to moderate his language "so that we will all feel secure when we're going about our jobs".
Mrs Cox's husband, Brendan, later tweeted he felt "sick at Jo's name being used in this way".
The Best way to honour her is to "stand up for what we believe in, passionately and with determination", he tweeted.
She told MPs: "I today have reported to The Police a threat against my child. That has been dismissed as 'humbug'.
"This is a disgraceful state of affairs and we must be able to find a way to conduct ourselves better. "Lib Dem leader Jo Swinson told MPs a threat had been made against her child
"There are others I believe who have left the estate, such has been the distress," she told MPs.
"In this, The Most peculiar and extraordinary of political times, the language that is used is incredibly important.
"We have evidence, whatever side of The Debate you are on, when you use word like 'surrender', 'capitulation', and others use the word 'traitor' and 'treason', there is a direct consequence.
Labour leader Jeremy Corbyn urged the Speaker to unite The Party leaders "to issue a joint declaration opposing any form of abusive language or threats and to put this message out to our entire community that we have to treat each other with respect".
Speaker John Bercow said he was "very open to convening a meeting of senior colleagues for the purpose of a House-wide public statement".
"But at a time of strong feelings we all need to remind ourselves of the effect of everything we say on those watching us," she tweeted.