what

What do you want? An abrupt, usually unfriendly enquiry as to what a person desires.
Used before a prepositional phrase to emphasise that something is taken into consideration as a cause or reason; usually used in combination with 'with' (see what with), and much less commonly with other prepositions.
Used to invite agreement or acknowledgment when something is assumed to be straightforward or already obvious to begin with; similar in function to “right?” and “as you know”.
Indicating a guess or approximation, or a pause to try to recall information.
Anything that; all that; whatever.
Which.
Which thing, event, circumstance, etc.: used in asking for the specification of an identity, quantity, quality, etc.
An expression of surprise or disbelief.
Clipping of what do you say?, used as a type of tag question to emphasise a statement and invite agreement, often rhetorically.
Used after a direct assertion to reinforce a disagreeing opinion.
Emphasizes the truth of an assertion made to contradict an evidently false assumption held by the listener.
Emphasises that something is noteworthy or remarkable in quality or degree, in either a good or bad way; may be used in combination with certain other determiners, especially 'a', less often 'some'.
Something; thing; stuff.
Which, especially which of an open-ended set of possibilities.
That which; those that; the thing(s) that.
In what way; to what extent.
That; which; who.
What did you say? I beg your pardon? This usage is often considered impolite, with the more polite "Pardon?" or "Excuse me?" preferred.
Used to form exclamations indicating that something is remarkable, in either a good or bad way.
Something that is addressed by what, as opposed to a person, addressed by who.
The identity of a thing, as an answer to a question of what.
Any ... that; all ... that; whatever.