| Abbreviation | Definition |
|---|---|
| SFTLR | Sorry For The Late Reply |
| SFYL | Sorry For Your Loss |
| SHIP | relationSHIP (not an acronym) |
| SIL | So In Love |
| SIM | Subject Is the Message |
| SIO | Spit It Out |
| SIRI | Search Information, Response Information |
| SIS | Sister |
| SIT | Stand for In Texting |
| SIZ | Size |
| SLF | Self |
| SLL- | So Long |
| SLO | Slow |
| SLR | Sorry Late Reply |
| SLS | Sweet Little Sister |
| SLT | Something Like That |
| SLW | Slow |
| SM | See Message |
| SMD | Suck My D*** |
| SMH | Shake My Head |