ceremonial, ceremonious
1. Ceremonial, meaning ‘with or concerning ritual or ceremony’, is a neutral descriptive adjective (as in ceremonial occasions / ceremonial dress / for ceremonial reasons). Ceremonious, meaning ‘having or showing a fondness for ceremony’, is a more evaluative and judgemental word. The difference can be seen by contrasting ceremonial entry with ceremonious entry: the first is an entry (in the abstract sense) marked by normal ceremony, whereas the second is an affectedly elaborate or grand entry (in the physical sense). Examples:

• Lord Mackan has had a busy programme of special ceremonial events on top of his normal Household chores —Sunday Express, 1981

• On the far side of the hearth the headman was sitting with his legs crossed, his back very straight, ceremoniously smoking a hookah —M. Connell, 1991.

2. Ceremonial is also used as a noun, meaning ‘proper formalities’:

• He had had to fight for everything he had done, fight the people who wanted to wrap him up safely and wheel him out for a bit of ribbon-cutting and ceremonial —P. Junor, 1991.

Modern English usage. 2014.