| on the house |
free, as a gift from a business establishment. |
| on the mend |
getting better, esp. in health; recuperating. |
| on the off chance |
with the very slight likelihood; against the faint hope. |
| on the shelf |
inactive or unused; put aside; reserved for future use or consideration. |
| on the sly |
secretly; stealthily. |
| on the spot |
at once; immediately. [2 definitions] |
| on the spur of the moment |
without much thought; on a sudden impulse. |
| on the whole |
all things considered; in general; for the most part. |
| on tiptoe |
standing or walking on the toes, esp. to proceed quietly or cautiously. [2 definitions] |
| onto |
to a position on or on top of. [2 definitions] |
| on top of |
in total control. [3 definitions] |
| onward |
toward a point or position ahead, as in space or time. [2 definitions] |
| ooze1 |
to seep out gradually and slowly, as liquid, gas, or sound may do. [7 definitions] |
| opal |
a variously colored, often iridescent, hydrated form of silica often used as a semiprecious stone. |
| opaque |
not allowing light to pass through. (Cf. transparent.) [6 definitions] |
| OPEC |
abbreviation of "Organization of Petroleum Exporting Countries." |
| open |
allowing entry or access; not shut, enclosed, or fastened. [27 definitions] |
| opener |
someone or something that opens. [3 definitions] |
| opening |
the act, process, or result of making open or causing to become open. [6 definitions] |
| openly |
in a way that involves no hiding or lying. |
| open-minded |
not having preconceptions or prejudgments; receptive; tolerant; impartial. |