Ageusia
Ageusia is the loss of taste functions of the tongue, particularly the inability to detect sweetness, sourness, bitterness, saltiness, and umami (meaning "pleasant/savory taste"). It is sometimes confused with anosmia – a loss of the sense of smell. Because the tongue can only feel texture and differentiate between sweet, sour, bitter, salty, and umami, most of what  we think of as the sense of taste actually comes from smell. Ageusia is a lot rarer than hypogeusia – a partial loss of taste – and dysgeusia – a distortion or change of taste.