plac·id 
(plăsĭd)
(plăsĭd)adj.
1.
a. Undisturbed by tumult or disorder; calm or quiet: led a placid life.
b. Not agitated physically; not disturbed: a placid stream.
2. Not easily upset or excited; mild or complacent: a placid demeanor. See Synonyms at calm.
[Latin placidus, from placēre, to please; see plāk-1 in the Appendix of Indo-European roots.]
pla·cidi·ty (plə-sĭdĭ-tē), placid·ness (plăsĭd-nĭs) n.
placid·ly adv.
- Indo-European root: del-
- Indo-European root: dem-
- Indo-European root: demə-
- Indo-European root: dent-
- Indo-European root: der-
- Indo-European root: derk-
- Indo-European root: deru-
- Indo-European root: deu-
- Indo-European root: deu-
- Indo-European root: deuk-
- Indo-European root: deuə-
- Indo-European root: dhegwh-
- Indo-European root: dheigh-
- Indo-European root: dher-
- Indo-European root: dhers-
- Indo-European root: dheu-
- Indo-European root: dheu-
- Indo-European root: dheub-
- Indo-European root: dheugh-
- Indo-European root: dheuə-
- Indo-European root: dhghem-
- Indo-European root: dhgh(y)es-
- Indo-European root: dhreg-
- Indo-European root: dhreibh-
- Indo-European root: dhreu-