Unprecedented
Unequalled, Unparalleled, Unmatched (Adjective).
Secretive
Tight-lipped, Discreet, Reticent (Adjective).
Pivotal
Central, Vital, Essential (Adjective).
Credibility
Reliability, Acceptability, Cogency (Noun).
Coherent
Logical, Rational, Cogent (Adjective).
Regrettable
Undesirable, Woeful, Distressing (Adjective).
Gulag
Concentration camps in Soviet Russia (Noun).
Retrospect
Reappraisal, Reconsideration (Noun).
Testimony
Proof, Evidence, Attestation (Noun).
Stunted
Inhibited, Impeded, Retarded (Adjective).
Distillation
Purification, Purgation, Filtration (Noun).
Totalitarian
Dictatorial, Autocratic, Despotic (Adjective).
Intermittently
Irregularly, Patchily, Sporadically (Adverb).
Defector
Traitor, Rebel, Renegade (Noun).
Perpetrator
Offender, Criminal, Wrong-doer (Noun).
Propitious
Auspicious, Favourable, Lucky (Adjective).
Desultory
Casual, Superficial, Erratic (Adjective).
Rudimentary
Basic, Elementary, Primary (Adjective).
Inoculated
Vaccinated, Immunized (Adjective).
Excrement
Human waste, Feces (Noun).
