(slang, informal) With all honesty and seriousness; affirmatively

To experiment in life; to find out what one is capable of.

plural of one-dayer

(chiefly US) The notion that one drop of white blood (i.e. any white ancestry at all) makes a person white.

Of an infant: to begin to support oneself on the legs, a prerequisite to walking.

The Hawaiian lobelioid Brighamia insignis

(UK, informal) Although it seems problematic now, it will ultimately succeed.

(idiomatic) Alternative form of bare one's teeth

To be sullen or sulky.

(idiomatic, slang, chiefly imperative) To stay calm; to not get flustered or angry.