only
UK[ˈəʊnli]US[ˈoʊnli]
adj
used to say that no other or others of the same group exist or are present
adj
used to say that something is the best, most important, or most suitable
adv
and no one or nothing more; solely
adv
no longer ago than; as recently as
conj
except that; but
Etymology
The word 'only' originates from the Old English word 'ānlīc', which was a compound of 'ān' (meaning 'one') and the suffix '-līc' (meaning 'like' or 'body'). This original form literally meant 'one-like' or 'single in kind'. Over time, through Middle English, the form evolved phonetically and semantically from 'anlich' and 'onlich' to the modern 'only'. The core semantic journey moved from the concrete sense of 'being the one of its kind' to the more abstract and functional meanings of exclusivity, restriction, and exception that it carries today as an adjective, adverb, and conjunction.
Analysis
The word 'only' is a simplex form derived from a single Old English root. It does not contain separable morphemes in its modern English spelling.
Examples
She was the only person in the room.
This is for your eyes only.
I would have gone, only I was too busy.