R. Finn

@MikeW The way I see it, the clues of the form [A + B] have three parts: a word defined by [A], a word defined by [+] (i.e. a synonym of [join] or [add to]), and finally a word defined by [B]. When the parts are "joined", the result forms a meaningful entry (which is not defined separately; that would probably have made it much too easy for a Thursday). As a bonus, the use of shaded boxes instead of circles makes the joining word a little like a hyphen (if you look at it the right way).

@Josephine Generally speaking, you can enter just the first letter of a rebus and it will be accepted. This is mentioned in the NYT guide to rebuses (linked in the column as well as elsewhere here in the comments).

@Mark P Hint: In a Tuesday puzzle, it might have been clued [Canniest, for "instance"].

@Francis I confidently filled in MAN and had to fix it later. (But if I see this clue again for a four letter entry, I can use AMAN.)

@George I've found that if you immediately go back and do the Friday puzzle (before it gets too late on Saturday), it will (may?) fill in the break and restore the streak. It may be too late now that it's Sunday, but give it a try anyway —there seems to be a little bit of a grace period (at least for me when doing the puzzle on the website, which I prefer to the app since then I can use a keyboard).