This is the 5810th most frequent Spanish word.
siguiera
"Siguiera" in English means "at least" or "even if" (depending on context).
In this sentence, 'siquiera' conveys the idea of 'even', emphasizing the minimal expectation that wasn't fulfilled.
Ni siquiera me llamó para avisar que llegaría tarde.
He didn't even call to let me know he would be late.
Here, 'siquiera' is used to underline the prohibition or restriction of even the slightest variation.
Quiero que sigas mis instrucciones al pie de la letra, ni siquiera cambies una palabra.
I want you to follow my instructions exactly, not even changing a word.
In this case, 'siquiera' is employed to imply a minimum effort, urging the listener to try at least.