Jim O'Donovan has taken Glasgow's Central College of Commerce to an employment tribunal claiming unfair dismissal. Mr O'Donovan wants the tribunal to order his reinstatement.
He admitted that he had approached Charles Boyce, a member of the board of management, who was chatting to two lecturers whose posts faced the axe as part of a restructuring exercise.
But Mr O'Donovan, president of the Educational Institute of Scotland's College Lecturers' Association, insisted: "It was a good natured and friendly approach. I did not approach him in an aggressive or threatening manner."
Mr O'Donovan said he asked Mr Boyce: "Do you want to sack these two women?"
He said it was an informal approach and the word "sack" had been used in an informal sense. The posts of the two lecturers concerned were to be made redundant but it was likely they would be found other jobs.
Mr O'Donovan denied he copied and circulated Mr Boyce's subsequent letter of complaint against him accusing him of unprofessional behaviour as a union official. He further denied he orchestrated a campaign against him.
Mr O'Donovan said he would have been quite happy to apologise. "I had not intended to upset Mr Boyce. I felt I had every right to ask about restructuring. I would expect him to withdraw the allegation of unprofessionalism against me."
But he was told Mr Boyce did not wish to participate in an offer of conciliation. Mr O'Donovan denied he had indicated to a colleague that Mr Boyce should be sent to Coventry.
The case proceeded to a disciplinary hearing and Mr O'Donovan denied he did anything to risk Mr Boyce's health, reputation or well-being but was dismissed for gross misconduct.
Earlier, the college principal denied the sacking had anything to do with Mr O'Donovan's union activities. Peter Duncan said that Mr O'Donovan's behaviour was "intimidatory" and amounted to harassment.
Mr Boyce, a former policeman who was student services co-ordinator, is no longer at the college.
The hearing continues.