The original meaning of the Tagalog word minsan is ‘once.’ It is now commonly understood in conversation to mean ‘sometimes’ as a short version of paminsan-minsan (from time to time).

once, sometimes

Minsan minahal kita.
I once loved you.

from time to time, occasionally,
sometimes, now and then

Minsan may duda ako.
Sometimes I have doubts.

minsan pa
once more

Mahalin mo ako minsan pa.
Love me once more.

used to describe a one-time thing

Minsanan ang pagkakataong ito.
This opportunity comes once.

Minsanan lang ang ganitong pagkakataon.
This kind of opportunity comes only once.

miminsan (not common)
just once

Ang kasalungat ng salitang minsan ay parati o lagi.
The opposite is the word ‘sometimes’ is ‘all the time’ or ‘always.’