Adjective; Variation in spelling and linguistic pronunciation of the
word "serious", but has the exact same meaning.
It can also be used as a modifier of another adjective, most interestingly: serious. See example below.
In some modern applications, the variation "Srsly" has the same effect, only it is
done by disemvoweling (removing of the vowels in a
word).
If you're aware that the letter "
y" is sometimes a vowel, kudos