Sentries are posted at borders, gates, or doors.
The gentry (in this case to referring to the general populace) bar their doors at night.
The first month is January, named after the Roman god Janus, the double-faced God of doorways, passages and thresholds.
You pass through the doorway (hence the slip), and dun is a brown color, referencing the color of wood, which most doors are made of. Though it’s not commonly referred to, the “lip of the door” is the part of the door that fits into the doorframe on the handle/knob side, particularly if the door is lipped or ridged in order to fit the door frame better.

Thanks to Helena for creating this and sending it in.

Sunglasses

Nuts.

People with nut allergies can die from eating nuts. Being hit in the nuts hurts (I speak from experience. Painful, painful experience). You eat nuts (unless you’re allergic, in which case you should run away). If someone says you’re nuts, it doesn’t mean you’re a peanut or an almond. Nuts and bolts hold things together. A climber’s nut or chock wedges into a rock. Instead of swearing, you can say, “Aww nuts!”. And finally, the nut on a violin is a small piece of hard material that supports the strings.