
Recalcitrant — stubbornly resistant to authority
Reticent — reserved, reluctant to speak
Sagacious — having keen mental discernment, wise
Sanguine — optimistic, positive (NOT related to blood on the GRE)
Soporific — causing sleep or drowsiness
Specious — superficially plausible but actually wrong
Stolid — calm, showing little emotion
Sycophant — a person who flatters to gain advantage
Taciturn — reserved, saying little
Tenacious — persistent, holding firmly
Synonym cluster: Reticent, taciturn, and laconic all describe someone who doesn't talk much. Reticent = reluctant to speak. Taciturn = habitually quiet. Laconic = using very few words when speaking.
Reference:
TaskLoco™ — The Sticky Note GOAT