a timer is paused when an astrisk prefixes the display (with -e) and/or when the timer ceases to update, e.g. count up or down. you can use the enter key to pause/unpause it (refer to the below example)
.nf
$ timer -e
* 05:45
.fi
.TP
.Bstoppingatimer
should you wish to stop a timer prematurely, or a timer which has no specified end condition, you may press the key combination that sends a killing signal to the program (e.g. a la SIGTERM) in your shell, which is usually ^C. the timer has no major places to clean up. however, memory leaks might occur on some operating systems due to no free()ing of resources.