her

The Latin verb haerēre meant something very concrete: to stick, to cling, to hang on and not let go. Imagine wet mud clinging to a boot, or two surfaces pressed together that won't come apart. That single physical image — one thing stuck to another — is the seed of the entire family, and English grew it in four directions, mostly by adding prefixes.

ad- (to, onto) + haerēre = adhere: to stick onto a surface. A stamp adheres to an envelope. From that literal sticking came a beautiful metaphor: you can also adhere to a rule or a plan — your behavior 'sticks to' the agreed line and doesn't peel away. So adhere, adherent (one who sticks to a cause), adherence, adhesive (the sticky stuff itself), and adhesion all share the one idea of sticking onto.

con- (together) + haerēre = cohere: to stick together. Here the focus shifts from 'A onto B' to 'all the parts holding as one mass.' A coherent argument is one whose parts stick together logically — nothing falls off, nothing contradicts. Cohesion is the force that keeps a group or a text bound as a unit; cohesive describes something that holds together that way. And incoherent is the failure of that bond — thoughts that won't stick together, speech that falls apart.

in- (in, inside) + haerēre = inhere: to stick inside something. If a quality sticks so deep inside a thing that you can't peel it off, it is inherent — a permanent, built-in part. The danger that is inherent in a job isn't added on; it's stuck into the very nature of the work. Inherently carries the same 'stuck-in, by its nature' sense.

The fourth branch hides behind a changed spelling. Latin had haesitāre, a frequentative of haerēre, meaning 'to keep sticking, to get stuck.' Picture someone walking whose feet keep sticking to the ground — every step is delayed, halting. That is exactly hesitate: to be stuck before acting, to pause from doubt. The hes- spelling (from the past participle haesus) marks this branch: hesitate, hesitant, hesitation, hesitancy. The physical 'stuck feet' became the mental 'stuck will.'

So every her-/hes- word traces back to the same gesture of clinging: stick onto (adhere), stick together (cohere), stick inside (inherent), or get stuck and can't move on (hesitate).

One warning about a famous look-alike. Heir, heritage, inherit, and hereditary feel like they belong here — and inherit even shares the in- + her- shape — but they descend from a completely different Latin word, hērēs (an heir), not from haerēre (to stick). They are same-spelling, different-source, and on this site they live under the separate root hered. An heir doesn't 'stick to' an estate; they receive it.