Tall order

From Fresh Dictionary

English

Noun

tall order

1. ((idiomatic{{#if:|, {{{2}}}{{#if:|, {{{3}}}{{#if:|, {{{4}}}{{#if:|, {{{5}}}{{#if:|, {{{6}}}{{#if:|, {{{7}}}{{#if:|, {{{8}}}{{#if:|, {{{9}}}}}}}}}}}}}}}}}}})) a big job; a difficult task

   Finishing everything tonight is a tall order, but I think I can do it with your help.