The Player recognizes special symbols such as N.C. (No Chord) which will result in the chordal instruments  dropping out for the duration of the N.C.  (Drums continue playing)
N.C.

To delete the N.C.symbol, tap (click) on the N.C. symbol (which should be highlighted) again; or for Mac, delete the letter "n" in the chord entry box.

Break*
Insert the word “Break” in the staff text** and the drums will stop with a shot on one (until the next double barline after which drums will resume).
Use in conjunction with N.C. if you want complete silence (e.g. for a pickup measure).

----
* Break feature added in 2021 updates:
Mac
2020.9 or higher (requires MacOS 10.13 High Sierra or higher)
(No Break feature in previous versions 2020.7 or lower)

iOS
2020.9 or higher (requires iOS 13 or higher)
(No Break feature in previous versions 2020.7 or lower)

Android
2022.1.2 or higher (requires OS 6 or higher)
[Also works in 2021.2 to 2021.8 (required OS 8 or later)]
(No Break feature in previous versions 2020.7 or lower)