It is a Japanese word and in the phonetics of that language there is a sound that is described in English as the sound of "TS". The T is very subtle and is a short sound just before the s sound. It is formed by placing your tongue at the front of the roof of your mouth while you begin to say the "S" sound.
It's originally a Japanese word, and there is a Japanese pronounciation romanised as 'tsu'...however, the English pronounciation does not have a way to pronounce 'tsu' in the way we will read it. So, English-speaking readers will just go with 'sunami'.
If you can imagine beat boxers doing the tse...tse.tse.. sound of the high hats in imitating the drums, that must be closest to the correct way to pronounce 'tsu'.
chocolate
tsunami
The spelling tsunami has a silent T (Japanese word meaning "harbor wave").
tsunami
The most known are tsar (czar) and tsunami.
T
The T is there because it is pronounced "tsunami", not "sunami", in its original language. If you choose not to pronounce the T in your language/dialect, that's fine. It is correctly pronounced as Tzunami, with a clear 'z'.
Yes, in the word 'glisten' the 't' is silent.
The word often is an antonym (opposite) of seldom, and has a silent 't'.
The 't' is silent.
The t is silent in whistling.
tsunami taxi