srsly is internet shorthand for seriously

A man who messes around with other men, but no one would ever know by looking or talking to him. Used by gay black men to identify masculine gay men or DL Brothas.

short for seriously with the vowels excluded

'seriously' spelled without the vowels.
used by lazy people on the internet.

Used often in txt, as double tapping or t9 is really annoying

Srsly is an internet shorthand or slang for seriously. It is either written out of laziness, a complete inability to spell or type, or in a failed attempt to be amusing.

An abbreviation for "seriously".