The paper focuses on the analysis of English phrasal verbs, i.e. complex lexemes that consist of a monolexemic verb and a special component of adverbial and prepositional origin standing in the postposition to the verb and forming with it more or less stable semantic and syntactic combinations. The research considers verbs with the postpositive components 'on' and 'off', defines their common and specific semantic and derivational features. The analysis of derivational processes within the verbs with postpositive components on and off enables to distinguish two types of derivation typical of them: word-building derivation (concerns the units which are formed from basic verbs by means of postpositive components on or off) and semantic derivation (the meanings of the units under consideration are formed from already existing meanings in the direction of metaphorization, restriction, extension or complication of meaning with additional semes). In this case, word derivation is more productive for phrasal verbs with both components-on and off. The classification of verbs with postpositive components on and off established in the study includes 8 main semantic types: physical action, phasal, abstract, psycho-mental, emotional, existential, possessive and relational verbs. Productivity of the basic semantic types of these verbs is different. Hence, for the verbs with the postpositive component off, the most common are verbs of physical action while for the verbs with the postpositive component on-psycho-mental verbs. In addition to the common meanings, specific meanings have been distinguished within verbs with the postpositive components on and off, i.e. meanings specific only to verbs with either of the postpositives (typical of solely phrasal verbs with on is the meaning of 'to continue', for those with off-the meaning