Gerund functioning as a mass noun referring to the act of talking about something.
Their discussing of the proposal continued late into the night.
Их обсуждение предложения продолжалось до поздней ночи.
discussinggerund / present participle Used attributively to describe entities engaged in discussion.
The discussing participants eventually reached consensus.
Обсуждающие участники в конечном итоге пришли к консенсусу.
discussgerund / present participle Used of someone or something that is currently engaged in discussion.