случа́йный meaning in English — accidental, adventitious, casual

English meaning

accidental adj Happening by chance rather than on purpose.
adventitious adj From an external source; not innate or inherent, foreign.
casual adj Relaxed and informal, especially in style, manner, or dress.
contingent adj Dependent on something else that is uncertain; conditional.
fortuitous adj Happening by chance, especially in a lucky or fortunate way.
haphazard adj Done without any clear plan or order; disorganized and random.
impromptu adj Done without any preparation or planning; spontaneous.
incidental adjective Happening as a minor accompaniment to something else, rather than as the main point.
occasional adj Happening from time to time, but not regularly or often.
random adj Happening or chosen without any particular pattern, plan, or reason.
sporadic adj Happening occasionally and irregularly, with no clear pattern.
transient adj Lasting only a short time; passing quickly.

случа́йный is used for these senses in English:

accidental Happening by chance, or unexpectedly; taking place not according to the usual course of things; by accident, unintentional. [from 16th c.]
anecdotal Of the nature of or relating to an anecdote.
contingent Possible or liable, but not certain, to occur.
fortuitous Happening by a lucky chance; lucky or fortunate.
haphazard Random; chaotic; incomplete; not thorough, constant, or consistent.
incidental Occurring by chance.
occasional Occurring or appearing irregularly from time to time, but not often; incidental.
random (statistics) Involving an outcome which is impossible to predict, but which may be represented by a probability distribution; in the ideal case, involving outcomes which are equally likely.