im|peach|ment / I mpiː tʃmənt/ (impeachments ) N‑VAR The impeachment of a senior official is the process of charging them with a crime which makes them unfit for office. □ There are grounds for impeachment.
im|pec|cable / I mpe kəb ə l/ ADJ If you describe something such as someone's behaviour or appearance as impeccable , you are emphasizing that it is perfect and has no faults. [EMPHASIS ] □ She had impeccable taste in clothes. ● im|pec|cably / I mpe kəbli/ ADV □ He was impeccably polite.
im|pecu|ni|ous / I mp I kjuː niəs/ ADJ Someone who is impecunious has very little money. [FORMAL ]
im|pede / I mpiː d/ (impedes , impeding , impeded ) VERB If you impede someone or something, you make their movement, development, or progress difficult. [FORMAL ] □ [V n] Fallen rock is impeding the progress of rescue workers.
im|pedi|ment / I mpe d I mənt/ (impediments )
1 N‑COUNT [oft without N ] Something that is an impediment to a person or thing makes their movement, development, or progress difficult. [FORMAL ] □ [+ to ] He was satisfied there was no legal impediment to the marriage.
2 N‑COUNT Someone who has a speech impediment has a disability which makes speaking difficult.
im|pel / I mpe l/ (impels , impelling , impelled ) VERB When something such as an emotion impels you to do something, it affects you so strongly that you feel forced to do it. □ [V n to-inf] …the courage and competitiveness which impels him to take risks.
im|pend|ing / I mpe nd I ŋ/ ADJ [ADJ n] An impending event is one that is going to happen very soon. [FORMAL ] □ On the morning of the expedition I awoke with a feeling of impending disaster.
im|pen|etrable / I mpe n I trəb ə l/
1 ADJ [usu ADJ n] If you describe something such as a barrier or a forest as impenetrable , you mean that it is impossible or very difficult to get through. □ …the Caucasus range, an almost impenetrable barrier between Europe and Asia.
2 ADJ If you describe something such as a book or a theory as impenetrable , you are emphasizing that it is impossible or very difficult to understand. [EMPHASIS ] □ His books are notoriously impenetrable. ● im|pen|etrably ADV [ADV adj] □ …impenetrably detailed reports on product sales.
im|pera|tive / I mpe rət I v/ (imperatives )
1 ADJ [usu v-link ADJ ] If it is imperative that something is done, that thing is extremely important and must be done. [FORMAL ] □ It was imperative that he act as naturally as possible.
2 N‑COUNT An imperative is something that is extremely important and must be done. [FORMAL ] □ The most important political imperative is to limit the number of U.S. casualties.
3 N‑SING In grammar, a clause that is in the imperative , or in the imperative mood, contains the base form of a verb and usually has no subject. Examples are 'Go away' and 'Please be careful'. Clauses of this kind are typically used to tell someone to do something.
4 N‑COUNT An imperative is a verb in the base form that is used, usually without a subject, in an imperative clause.
im|per|cep|tible / I mpə r se pt I b ə l/ ADJ Something that is imperceptible is so small that it is not noticed or cannot be seen. □ Brian's hesitation was almost imperceptible. ● im|per|cep|tibly / I mpə r se pt I bli/ ADV [usu ADV with v, oft ADV adj] □ The disease develops gradually and imperceptibly.
im|per|fect / I mpɜː r f I kt/
1 ADJ Something that is imperfect has faults and is not exactly as you would like it to be. [FORMAL ] □ We live in an imperfect world. ● im|per|fect|ly ADV [usu ADV -ed/adj] □ This effect was imperfectly understood by designers at that time.
2 N‑SING In grammar, the imperfect or the imperfect tense of a verb is used to describe continuous situations or repeated actions in the past. Examples are 'I was reading' and 'they were eating'.
im|per|fec|tion / I mpə r fe kʃ ə n/ (imperfections )
1 N‑VAR An imperfection in someone or something is a fault, weakness, or undesirable feature that they have. □ [+ in ] He concedes that there are imperfections in the socialist system.
2 N‑COUNT An imperfection in something is a small mark or damaged area which may spoil its appearance. □ [+ in ] …imperfections in the cloth.
im|perial / I mp I ə riəl/
1 ADJ [ADJ n] Imperial is used to refer to things or people that are or were connected with an empire. □ …the Imperial Palace in Tokyo.
2 ADJ [ADJ n] The imperial system of measurement uses inches, feet, and yards to measure length, ounces and pounds to measure weight, and pints and gallons to measure volume.
im|peri|al|ism / I mp I ə riəl I zəm/ N‑UNCOUNT Imperialism is a system in which a rich and powerful country controls other countries, or a desire for control over other countries.
im|peri|al|ist / I mp I ə riəl I st/ (imperialists ) ADJ [usu ADJ n] Imperialist means relating to or based on imperialism. □ The developed nations have all benefited from their imperialist exploitation. ● N‑COUNT An imperialist is someone who has imperialist views.
im|peri|al|is|tic / I mp I ə riəl I st I k/ ADJ If you describe a country as imperialistic , you disapprove of it because it wants control over other countries. [DISAPPROVAL ]
im|per|il / I mpe r I l/ (imperils , imperilling , imperilled ) in AM, use imperiling , imperiled VERB Something that imperils you puts you in danger. [FORMAL ] □ [V n] You imperilled the lives of other road users by your driving.