documentclass{article}
usepackage{tikz}
usetikzlibrary{shapes.geometric}
newcommand{warningsign}{tikz[baseline=-.75ex] node[shape=regular polygon, regular polygon sides=3, inner sep=0pt, draw, thick] {textbf{!}};}
begin{document}
warningsign Warning
end{document}

documentclass{article}

usepackage{fourier}

begin{document}

danger

end{document}

documentclass{article}

begin{document}

{fontencoding{U}fontfamily{futs}selectfontchar 66relax}

end{document}

LaTeX Font Warning: Font shape `U/futs/m/n' undefined
(Font)              using `U/cmr/m/n' instead on input line 5.

newcommand*{TakeFourierOrnament}[1]{{%
fontencoding{U}fontfamily{futs}selectfontchar#1}}
newcommand*{danger}{TakeFourierOrnament{66}}

documentclass{article}

newcommand*{TakeFourierOrnament}[1]{{%
fontencoding{U}fontfamily{futs}selectfontchar#1}}
newcommand*{danger}{TakeFourierOrnament{66}}

begin{document}

danger

end{document}

documentclass{article}
usepackage[utf8]{inputenc}
usepackage{xcolor}
usepackage{newunicodechar}

newcommandWarning{%
 makebox[1.4em][c]{%
 makebox[0pt][c]{raisebox{.1em}{small!}}%
 makebox[0pt][c]{color{red}Large$bigtriangleup$}}}%

newunicodechar{⚠}{Warning}

begin{document}

    Do⚠not⚠put your finger

    on the power plug.

end{document}

documentclass{article}
usepackage{stackengine}
usepackage{scalerel}
usepackage{xcolor}
newcommanddangersign[1][2ex]{%
  renewcommandstacktype{L}%
  scaleto{stackon[1.3pt]{color{red}$triangle$}{tiny !}}{#1}%
}
begin{document}
This is a danger sign 5ex tall: dangersign[5ex]par
Here is the default (2ex) size: dangersign
end{document}

documentclass{article}
usepackage{stackengine}
usepackage{scalerel}
usepackage{xcolor}
newcommanddangersign[1][2ex]{%
  renewcommandstacktype{L}%
  scaleto{stackon[1.3pt]{color{red}$triangle$}{tinybfseries !}}{#1}%
}
begin{document}
This is a danger sign 5ex tall: dangersign[5ex]par
Here is the default (2ex) size: dangersign
end{document}

documentclass{article}
usepackage{fontspec}
setmainfont[Ligatures=TeX]{STIXGeneral}
newcommandwarningsign{⚠}
begin{document}
    warningsign Warning
end{document}

newcommandwarningsign{symbol{"26A0}}

documentclass{article}
usepackage{fontawesome}

begin{document}

faWarning, Warning: This product contains peanuts, %
which might not be very suitable for certain individuals.

end{document}