And what do you want to know?
Yes, that sword's tier is higher than YOUR tier.
44 level = 5 tier
54 sword's level = 6 tier sword
.
You wrote about your merc. Do you want to equip that sword with level 54 to your merc level 50, but the game says that you can't, because tier is higher than your mercs?
Excatly: are you are asking about merc and that sword?