suffix
Attaches to the -masu stem of a verb to express that an action occurs while another contradictory or unexpected situation holds. Often used in formal or written contexts.
See also: つつ
彼は悪いと知りつつも、嘘をついてしまった。
Even though he knew it was wrong, he ended up telling a lie.
危険だと分かっていつつも、彼は救助に向かった。
Despite knowing it was dangerous, he went to the rescue.