opportunist

[ op-er-too-nist, -tyoo- ]
/ ˌɒp ərˈtu nɪst, -ˈtyu- /

noun

a person who practices opportunism, or the policy of adapting actions, decisions, etc., to effectiveness regardless of the sacrifice of ethical principles: He is an extreme opportunist and always thinks the ends justify the means.

Example sentences from the Web for opportunist

British Dictionary definitions for opportunist

opportunist
/ (ˌɒpəˈtjuːnɪst) /

noun

a person who adapts his actions, responses, etc, to take advantage of opportunities, circumstances, etc

adjective

taking advantage of opportunities and circumstances in this way

Derived forms of opportunist

opportunism, noun