Someone who is aloof, or is perceived as such, is disinterested or reticent and reserved. Aloof suggests a cool, detached, and distant air, which makes sense considering this term sailed into English on cool winds. Aloof is formed from a- (here meaning “into” or “toward”) and luff, a nautical term referring to the forward edge of a fore-and-aft sail; its earliest sense in English was as an adverb meaning “to the side from which the wind blows.”

A full train station is filled to capacity. A teeming train station is beyond full—it’s abounding or swarming with people. Teeming comes from the verb teem meaning “to abound or swarm,” or “to be prolific or fertile.” The earliest sense of the verb was “to produce offspring.” Given the fertile history of this word, it is not surprising that teem often appears in close proximity to the word life, as in the case of a tide pool that is teeming with life.

Relationship is a general term that can be applied to a wide range of connections, involvements, or associations—each of us has a particular relationship with technology, for instance (some better than others!). The noun rapport is more specific: this term is used of relations between people and suggests a harmonious and sympathetic type of connection. For example, a teacher might try to establish a close rapport with students—a connection marked by mutual understanding and good communication.