What it means
をものともせず expresses acting courageously in the face of an obstacle, criticism, danger, or other adverse condition, while treating it as something not worth fearing or being hindered by. It often conveys admiration for the subject's determination and is common in formal writing, reports, biographies, and elevated narration. The construction usually follows a noun representing the difficulty and connects to the main clause describing the determined action.
Usage note
をものともせず is formal and somewhat literary, so it is less natural for ordinary minor inconveniences. The noun before it normally names a substantial obstacle or opposition, such as danger, criticism, injury, or hardship.
How to use it
厳しい批判をものともせず、研究者は新しい理論を発表しました。
Despite severe criticism, the researcher announced a new theory.
厳しい批判をものともせず、研究者は新しい理論を発表した。
Despite severe criticism, the researcher announced a new theory.