KUALA LUMPUR — Fatwa, imam, hajj — words that have passed the lips of millions of people in the Muslim world and beyond. Here in Malaysia, where religious tensions periodically simmer and boil, non-Muslims can be jailed up to a year for writing or uttering them outside of an Islamic context.

More than two dozen words and phrases are banned for non-Muslims by a law that ostensibly seeks to prevent members of other religions, chiefly Christians, from trying to convert Muslims, who make up about 60 percent of Malaysia’s population.

Until recently the ban, which carries a maximum one-year prison sentence, was obscure: it has only been used once in court, according to Pawancheek Marican, a Malaysian lawyer who has written about it.

Now a debate about these banned words has become the latest chapter in what is known here as the Allah issue.