Lack of interest can be easily reflected by the symbols depicting the motion of hands ┐ ┌ or ╮ ╭, in addition, slashes of various types and other long symbols resembling hands can be used. All these can be supplemented with indifferent eyes: the most popular combinations are ー ー, ˇ ˇ and similar which do not express any emotions.
ヽ(ー_ー )ノ | ヽ(´ー` )┌ |
┐( ̄ヘ ̄)┌ | ヽ( ̄~ ̄ )ノ |
┐( ̄~ ̄)┌ | ┐(︶▽︶)┌ |
┐( ´ д ` )┌ | ╮(︶︿︶)╭ |
╮(︶▽︶)╭ | ╮( ˘ 、 ˘ )╭ |
┐( ̄ヮ ̄)┌ | ᕕ( ᐛ )ᕗ |
┐(‘~` )┌ | ヽ(  ̄д ̄)ノ |
╮( ̄_ ̄)╭ | ヽ(ˇヘˇ)ノ |
╮( ̄~ ̄)╭ | ¯\_(ツ)_/¯ |
┐( ̄∀ ̄)┌ | ┐( ˘ 、 ˘ )┌ |
┐( ˘_˘ )┌ | ╮( ˘_˘ )╭ |