These words refer to an uneasy or exasperated response to external factors or causes. Unsettle is the least intense of these, suggesting someone who has been unnerved or vaguely disquieted by something; the cause may be a specific distraction or a more indefinable mood or atmosphere: unsettled by the constant wailing of an infant in the next flat; unsettled by the cold formality of the office. Even in the active voice, the word does not suggest an intentional attempt to unnerve someone so much as a subjective or intuitive response to an existing state of affairs. One would not be likely to say: He deliberately unsettled me. But one could say: Oddly enough, his presence in the room unsettled me. By contrast, annoy can indicate both an intentional disturbance and a disturbed response.

• Why do you insist on annoying her?; I was annoyed by the way he kept mumbling something over and over to himself.

In any case, annoy indicates a greater degree of emotional upset than does unsettle : His whistling unsettles me a bit, but it doesn’t really annoy me all that much.

Irritate suggests a repeated, abrasive action that annoys a person by draining him of patience or good humour; nothing is too trivial to irritate , if the temper of the observer is highly strung or petulant: Her habit of tapping her fingers on the chair while she read the newspaper irritated him. Nettle suggests being temporarily aroused to anger or pique, often because of something considered damaging to one’s self-respect: nettled by her wilful disregard of his advice; nettled by the critic’s casual rejection of his arguments. Nettle often implies, as in these examples, a sense of indignation occasioned by a real or fancied slight.

Rile is in every way an intensification of annoy , but it is also more informal; the word emphasizes response without suggesting an intended cause: riled by his unthinking rudeness; I didn’t mean to get you all riled up over nothing. Put out is related more closely to unsettle than to the previous pair. It points to the vague dissatisfaction of someone who has been displeased, inconvenienced or disappointed.

• He was put out by the way everyone at the party ignored him; She tried to get her word done but was terribly put out by the constant interruptions of the workmen; Only a sullen silence suggested how put out he was over not getting his promotion.

As in the last example, the word can imply a minimal, passive or withdrawn response; this may be true for unsettled also. By contrast, annoy and irritate suggest a more agitated or noticeable response. In the active voice, put out refers more exclusively to inconvenience: I hope we haven’t put you out by staying so late.