frenemy
Someone who has traits of an enemy and a friend.
Painting with a bland stroke, hardly mixing color on palette or canvas, working neatly, quickly, deftly, and a bit hygienically—like an Old World gentleman—over his “spontaneous” projects—indeed, “tickling” his way along, to borrow frenemy Picasso's devastating verb—he [Henri Matisse] seems never to be deeply involved or even slightly carried away by his work.
A fair-weather friend who is also a rival.
So, we're definitely not going to be friends with Ferguson? Maybe we can be frenemies. A love-hate relationship's the next best thing.
Where it comes from
Blend of friend + enemy. Invented independently multiple times. Attested in 1952 without any scare quotes or self-referential apology, clearly suggesting that the writer expected his audience to be unsurprised by encountering the word, but used by other writers in 1979 and 1992 in ways that indicate that those writers considered it a nonce blend and expected that their audiences would view it that way too; these examples are evidence that the word existed for many decades during which it was not yet widely familiar or established (which it now is).
Adapted from the Wiktionary entry frenemy (CC BY-SA 4.0).