What is the ruling on holding a religious competition where members are asked to recall a difficult word from the Qur’an and then provide its meaning, and is this considered mockery of religion?

There is no harm in organizing competitions in Islamic sciences like Tafsir (Qur'anic exegesis) and others, with the intention of benefiting the participants. This is not considered mockery of religion; rather, it is a good deed, as it restricts competitions that contain violations by providing a beneficial, Sharia-compliant alternative.