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"
any of the more than 100 known substances (of which 92 occur naturally) that cannot be separated into simpler substances and that singly or in combination constitute all matter
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"
characterized by care and perseverance in carrying out tasks; "a diligent detective investigates all clues"; "a diligent search of the files"
quietly and steadily persevering especially in detail or exactness; "a diligent (or patient) worker"; "with persevering (or patient) industry she revived the failing business"
prevent the progress or free movement of; "He was hampered in his efforts by the bad weather"; "the imperialist nation wanted to strangle the free trade between the two small countries"