Desperate, Certain Death, Sure Death
な adjective and の adjective
ひっし
必死にがんばっても、どうにもならないこともある。
Even if I try desperately, it might still be futile.
わたしのそ父は、必死のかくごでせんじょうに向かったそうです。
I heard that my grandfather went to the war front prepared to die.
「隊長、私はどうしても火星に戻る必要があるんです。アイフォンを忘れてしまったのです。」彼は必死に頼んだ。
"Captain, I really need to return to Mars. I left my iPhone there," he said desperately.
Your future consists of certain death. How would you feel in this situation? Probably very frantic and desperate.
Another translation for this word is simply certain death, though I'd rather you learn one of the first two before this one if you can.
The readings are the on'yomi readings, though 必 (ひつ) gets shortened to ひっ. In your desperate situation just imagine that you're trying to get out of it, and to do so you move the つ only to find a smaller っ blocking your way. It is certain death.