Quell.  That’s a good word.  It’s not commonly used and it sounds unusual.  It starts with a ‘k’ sound so it’s not that nice sounding, but it does end with an ‘ell’ sound, so that saves it I guess.

Suppress.  That sounds even better.  It’s a bit more common, although still not widely used.  You’d maybe find it in journalistic prose, like newspaper stories or new shows, but not in normal everyday conversation.  But the sound of the word is nice, with all those sibilants.  The ‘p’ in the middle is the hardest sounding letter in the bunch, but that’s about it.

Pacify.  The second word sounds better, but this one isn’t so bad either.  The ‘c’ in the middle is soft sounding, and the word is still feminine overall.  It’s another uncommon word, not entirely formal, but it’s more of a ‘discussion’ word rather than a ‘conversation’ word.

Check.  This is one is short and to the point.  Curt.  It’s not pleasant sounding either.  This word exists just to get the job done.  I would even suggest that it’s a bit onometopoeic in that it’s more like a sound for something, the action of ticking something off, than an actual word.  Although that’s not true of course.

Subdue.  This word is… ordinary.  It fades into the background of other words, which makes it completely suitable for what it means I guess.  It’s not an ugly sounding word, but it’s not particularly pretty either.  It’s neutral in terms of sound.

Stem.  This is another feminine sounding word.  It suggests something long and elegant, because of the imagery of the word as a noun of course.  As a verb, I think it’s a softer way of saying ‘to cut’.  More like a gentle action with some sharp clippers rather than with a hacking motion using a dull knife.