Learn English – ny relation between the meanings of the word “cataract”

On the surface, one might think that ingenious is somehow based on the word genius. Interestingly, this is not true.

The word ingenious does not actually have the in- prefix for negation. Instead, it comes originally from the Latin ingeniōsus, which means "intellectual, talented, ingenious". At times in history it was also spelled "engenious". Indeed, ingeniōsus appears to be the same root that gave us the word engine.

Genius was originally different, but evolved to have a meaning that is similar to ingenious. It came to us from Latin, but it was originally Greek. According to the OED, it mainly had the meaning of, approximately, "genie" or similar type of spirit, in Latin. Figuratively, it was also used to mean "characteristic disposition; inclination; bent, turn or temper of mind." In English, German, and most of the Romance languages aside from Latin, it had the meaning of "natural ability" starting around the 1600s. The OED speculates that the meaning of genie was pushed towards the meaning of ingenious because of "confusion" between the two (that is, their superficial similarity).

-ship is added to a noun to establish status or condition.

1. Indicating a state or a condition, e.g. to be in a friendship.
2. Indicating the qualities belonging to a class of people, e.g. craftsmanship.
3. Indicating office or profession, e.g. ambassadorship.

Quote from http://www.randomhouse.com/wotd/index.pperl?date=19990225:

The suffix -ship has been studied in some detail, but most of that detail is irrelevant to all but the most hardcore etymologist. The most important thing, in terms of its origin, is that it is unrelated to the word ship meaning 'a vessel, especially a large seagoing vessel'.

-ship is a suffix used to form nouns of state or condition, chiefly added to nouns and especially personal nouns. In Old English it was widely used with adjectives and participles, but only two of these survive (hardship and worship, from an adjective meaning 'worthy').

The uses can be divided into ever-finer distinctions, but there are some basic categories. It can denote 'quality; condition' (kinship; friendship 'the condition of being a relative/friend'). It can denote 'skill; act; power' (scholarship 'the acts of a scholar'; horsemanship 'the skill of a horseman'). It can denote 'number' (readership; listenership 'number of readers/listeners'). It can denote 'profession; office; position' (professorship 'the profession of a professor'). It can denote rank or title (ladyship; lordship).

The suffix was common in Old English, and is ultimately a form of the ancestor of the Modern English verb shape, in the sense 'to create; form'. Cognate suffixes are found in many Germanic languages; a form occasionally encountered is the German Wissenschaft 'science', from Wissen 'knowledge' and -schaft '-ship'.