Backseat driver

From Fresh Dictionary

English

Noun

backseat driver

1. A passenger in a car who insists on giving the driver directions.
2. ((idiomatic{{#if:|, {{{2}}}{{#if:|, {{{3}}}{{#if:|, {{{4}}}{{#if:|, {{{5}}}{{#if:|, {{{6}}}{{#if:|, {{{7}}}{{#if:|, {{{8}}}{{#if:|, {{{9}}}}}}}}}}}}}}}}}}})) By extension, anybody offering unsolicited or unwelcome advice.