You searched for: “adversatives
adversative (s) (noun), adversatives (pl)
A word, phrase, or clause that expresses opposition or a contrast: Examples of adversatives include such conjunctions as, "but" or "although".

Mark was talking to a friend about a trip and the possible weather conditions and he expressed an adversative when he said, "We should set a date for our journey, but if the weather is too bad, we need to plan an alternative time."