Opportunist (noun)

1. A person who takes advantage of opportunities as they arise, often regardless of planning or principle.
2. A person who adapts their views or actions to suit their circumstances, rather than adhering to a particular principle or ideology.

Origin:

Late 19th century: from french opportuniste, from opportunité "opportunity" (see opportunity).

Examples:

1. The politician was criticized for being an opportunist who would say anything to win votes.
2. The businessman was an opportunist who was always looking for ways to make a quick profit.
3. He was a career opportunist who would do anything to get ahead.
4. The opportunist took advantage of the situation and made a fortune.
5. He was an opportunist who had no principles and would do anything for personal gain.