Se il contesto è questo:
(...) His multilateral UN credentials also meant that the Labour party was likely to tolerate his political promiscuity — Malloch Brown had flirted with the SDP in the 1980s and done a turn at David Cameron’s first Tory conference — and not kick up a fuss over the financial work he had taken on after leaving the UN. (...)
http://www.spectator.co.uk/the-magazine/politics/335151/the-...
Ha un'accezione alquanto negativa, ma prima si usano i termini "promiscuity" e "had flirted", perciò - sempre ammesso che il contesto sia quello - puoi tradurre con "cambiare bandiera, fare il voltagabbana".