to say nothing of ...
and in addition there is:
It would be an enormous amount of work, to say nothing of the cost.

[TahlilGaran] Advanced Learner's Dictionary ▲

to say nothing of
to say nothing of (something)
and also something else.
It is difficult to escape the cold, to say nothing of the wind and rain.

Usage notes: used to add emphasis to something you have just said
Related vocabulary: not to mention someone/something

[TahlilGaran] English Idioms Dictionary ▲

to say nothing of something
to say nothing of (something)
and also something else.
It is difficult to escape the cold, to say nothing of the wind and rain.

Usage notes: used to add emphasis to something you have just said
Related vocabulary: not to mention someone/something

[TahlilGaran] English Idioms Dictionary ▲

to say nothing of
• to say nothing of (someone or something)
to not even mention the importance of someone or something
The hotel itself was very expensive to say nothing of the cost of the restaurants in the hotel.

[TahlilGaran] English Idioms Dictionary ▲

to say nothing of something
• to say nothing of (someone or something)
to not even mention the importance of someone or something
The hotel itself was very expensive to say nothing of the cost of the restaurants in the hotel.

[TahlilGaran] English Idioms Dictionary ▲

to say nothing of
Without ever needing to speak of; in addition to; besides.
■ Used to add something to what you have said or explained.
Dave is handsome and smart not to mention being a good athlete.
They have three fine sons, not to speak of their two lovely daughters.
Sally takes singing and dancing lessons to say nothing of swimming and tennis lessons.
Compare: LET ALONE, TO SPEAK OF.

[TahlilGaran] English Idioms Dictionary ▲

to say nothing of someone
• to say nothing of (someone or something)
to not even mention the importance of someone or something
The hotel itself was very expensive to say nothing of the cost of the restaurants in the hotel.

[TahlilGaran] English Idioms Dictionary ▲