Yes, tag is playable
...and is worth 5 points.
Found in the following dictionaries
Enable (Words with friends)
SOWPODS (Collins Scrabble Words)
OTCWL2014 (NASPA Word List 2014)
TWL06 (NASPA List 2006)
"Tag" Definition
noun
A brief quotation used in a discourse to give it an air of erudition or authority: Shakespearean tags.
A cliché, saw, or similar short, conventional idea used to embellish a discourse: These tags of wit and wisdom bore me.
A designation or an epithet, especially an unwelcome one: He did not take kindly to the tag of pauper.
A dirty, matted lock of wool.
verb-transitive
Baseball To touch (a base runner) with the ball in order to put that player out.
Sports To touch (the runner) as a substitute for tackling in touch football.
To add a taggant to: explosives that were tagged with coded microscopic bits of plastic.
To add as an appendage to: tagged an extra paragraph on the letter.
To charge with a crime: The suspect was tagged for arson.
phrasal-verb
Tag up Baseball To return to and touch a base with one foot before running to the next base after a fielder has caught a fly ball.
verb-intransitive
To follow after; accompany: tagged after me everywhere; insisted on tagging along.
verb
to provide or mark with or as if with a tag as.
To supply with an identifying marker or price.
To provide with a name or epithet.
To put a ticket on (a motor vehicle) for a traffic violation.
To deface with a graffito usually in the form of the defacer's nickname.
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