not changeable or subject to change; "a fixed and unchangeable part of the germ plasm"-Ashley Montagu; "the unchangeable seasons"; "one of the unchangeable facts of life"
inquire into; "the students had to research the history of the Second World War for their history project"; "He searched for information on his relatives on the web"; "Scientists are exploring the nature of consciousness"
attempt to find out in a systematically and scientific manner; "The student researched the history of that word"
commonplace and ordinary; "the familiar everyday world"
found in the ordinary course of events; "a placid everyday scene"; "it was a routine day"; "there's nothing quite like a real...train conductor to add color to a quotidian commute"- Anita Diamant
marked by unjust severity or arbitrary behavior; "the oppressive government"; "oppressive laws"; "a tyrannical parent"; "tyrannous disregard of human rights"
weighing heavily on the senses or spirit; "the atmosphere was oppressive"; "oppressive sorrows"
the quality of being difficult; "they agreed about the difficulty of the climb"
a factor causing trouble in achieving a positive result or tending to produce a negative result; "serious difficulties were encountered in obtaining a pure reagent"
a condition or state of affairs almost beyond one's ability to deal with and requiring great effort to bear or overcome; "grappling with financial difficulties"