From Longman Business Dictionary
opportunistop·por·tun·ist /ˌɒpəˈtjuːnəstˌɑːpərˈtuː-/ noun [countableC] a person or organization that is willing to use every chance to gain an advantage or make moneyThese companies represent a growing band of economic opportunists - they move with lightning speed whenever an opportunity opens.
—opportunistic adjectiveadjWe’re a very opportunistic company, continually looking to strengthen ourselves strategically in individual market segments.
—opportunistically adverbadvWe’re learning how to sell much more opportunistically.