Foibles are minor flaws or shortcomings in someone's character or behavior. In fencing, foible refers to the weakest part of a sword's blade, between the middle and point.

// You have to be able to laugh at your own foibles.

Deleterious is a word used in formal speech and writing to describe something that is damaging or harmful, usually in a subtle or unexpected way.

// Though effective at keeping pests away from plants, the spray is no longer used because of its deleterious effects on the respiratory system.

An accoutrement is a piece of clothing or equipment that is used in a particular place or for a particular activity. In military contexts, accoutrement refers specifically to a soldier's outfit. The word can also refer to an identifying and often superficial characteristic or device. Accoutrement in any of its uses is often pluralized.

// They have all the accoutrements that a baker could ever want, including a robust collection of cookie cutters and a veritable wardrobe of vintage aprons.

Valedictory describes something expressing or containing a farewell.

// The valedictory speech given by the department chair moved several faculty members to tears.

An interloper is a person who intrudes in a place or sphere of activity; they are not wanted or welcome by the other people present.

// Summer residents were regarded as interlopers who lacked a commitment to the town's welfare.

As a synonym of aromatic, the word redolent can describe something that has a noticeable smell without specifying the scent, but more often it is accompanied by of or with and means “full of a specified fragrance,” as in “redolent with incense.” Redolent can also describe something that causes thoughts or memories of something, as in “music redolent of the 1980s.”

// The late-spring meadow was redolent of wildflowers and petrichor.

Crux refers to the most important part of something (such as a problem, issue, or puzzle). It is often used in the phrase "the crux of."

// The crux of the problem is that the project's budget is totally inadequate.

Permutation is a formal word for any one of the many different ways or forms in which something exists or can be arranged. It can also refer to a major or fundamental change in something based primarily on rearrangement of its existing elements. Permutation is usually used in its plural form.

// Early permutations of the design look nothing like the final result.

// The system has gone through several permutations.

Cohort refers to a group or band of individuals, as in “a cohort of supporters.” It can also be used for a group of individuals who have a statistical factor (such as age) in common in a demographic study, as in “a cohort of people born in the 1980s.” Cohort can be used for individuals too, as for a friend, companion, or colleague, but it is almost always used in its plural form.

// I wouldn’t have made it through graduate school without the help of my supportive cohort.

. a favorite saying of a sect or political group

. a manner of speaking or acting that is distinctive of a particular group

. a widely held belief