sincer-o, -a, sincere.
singular, singular, strange.
singularísim-o, -a, very singular; very strange.
sino, but; — que, but.
sinsabor, m., displeasure, sadness.
sintiendo, pres. part. of sentir.
síntoma, m., symptom.
siquiera, at least.
sirva, pres. subj. of servir.
sirve, pres. of servir.