Is the name "Mu'ayyad" among the disliked names? And what does it mean?

The rule for names forbidden by Islamic law is that they involve servitude to other than Allah, or are among the names and attributes specific to Him, or contain dispraise, ugliness, or self-praise. "Al-Mu'ayyad" (the Supported/Supporter) is an active or passive participle derived from ta'yeed, which means strengthening. There is no religious prohibition against naming with it, but it is preferable to choose good names, such as the names of prophets and companions.