This is the 427th most frequent Finnish word.
parasta
"Parasta" means "the best" in English.
The word 'parasta' is the superlative form in the partitive case, referring to 'the best thing of something in general'.
Parasta päivässä on auringonpaiste.
The best part of the day is the sunshine.
Here, 'parasta' describes an action being the optimal or best effort currently.
Teemme parasta, mitä voimme.
We are doing the best we can.
In this case, 'parasta' is used to signify a superlative action or thing perceived uniquely as the most outstanding.