"On this occasion" means at this particular time or for this specific event. It refers to a specific instance or occurrence that is being referred to in the context.
Appropriate means 'fitting for the occasion'.
A festive occasion or celebration.
Nothing.The correct phrase is "on this occasion" and just means "when this is occurring" or "while this is happening." An occasion is just a happening or event.
Inappropriate means not suitable for a particular occasion.
Felicitation speech means to congratulate one in an special occasion.
To be modest means also to be appropriate for occasion and time.
It means dress in casual clothes, preferably dirty.
at least one of the population means is different from the other
It means to celebrate something, such as an occasion or holiday, etc.
There is no such word as unparticular. There is in particular which means belonging to, a thing, group. occasion, or a specific person.
even the most incompetent can get lucky on occasion
It means that it is a special occasion. You take out the fine China plates, crystal glasses, and fancy silverware when it is a special occasion or an important meal, and you really want to impress your guests.