Yes, that is playable
...and is worth 6 points.
Found in the following dictionaries
Enable (Words with friends)
SOWPODS (Collins Scrabble Words)
OTCWL2014 (NASPA Word List 2014)
TWL06 (NASPA List 2006)
"That" Definition
adverb
To such an extent or degree: Is your problem that complicated?.
conjunction
Used to introduce a noun clause that is usually the subject or object of a verb or a predicate nominative: "That contemporary American English is exuberantly vigorous is undeniableā ( William Arrowsmith).
Used to introduce a subordinate clause modifying an adverb or adverbial expression: will go anywhere that they are welcome.
Used to introduce a subordinate clause stating a result, wish, purpose, reason, or cause: She hoped that he would arrive on time. He was saddened that she felt so little for him.
Used to introduce a subordinate clause that is joined to an adjective or noun as a complement: was sure that she was right; the belief that rates will rise soon.
Used to introduce an anticipated subordinate clause following the expletive it occurring as subject of the verb: It is true that dental work is expensive.
pronoun
According to what; insofar as: He never knew her, that I know of.
In, on, by, or with which: each summer that the concerts are performed.
The one, kind, or thing; something: She followed the calling of that which she loved.
Used as a relative pronoun to introduce a clause, especially a restrictive clause: the car that has the flat tire.
Used to emphasize the idea of a previously expressed word or phrase: He was fed up, and that to a great degree.
idiom
At that In addition; besides: lived in one room, and a small room at that.
At that Regardless of what has been said or implied: a long shot, but she just might win at that.
That is To explain more clearly; in other words: on the first floor, that is, the floor at street level.
adjective
Being the one further removed or less obvious: That route is shorter than this one.
Being the one singled out, implied, or understood: that place; those mountains.
Being the person, thing, or idea specified, mentioned, or understood.
Being the one specified .