How to put a gamma into my latex document

Question

I have \usepackage[utf8]{inputenc}

I typed

something something γ something

I am getting the error "Package inputenc Error: Unicode character γ (U+03B3)" and it won't render in the output

How can I make that and other modern greek render?

I don't want to use [english, greek]{babel} and select language just for single words at a time

$\gamma$ isn't a solution because math-mode gamma is italicised, and I want the gamma I type using my keyboard γγγγ to render as exactly that (in the typeface that the document is in or whichever most similar typeface supports it)

Answer 1

In LuaLaTeX or XeLaTeX, load fontspec and select fonts that contain Greek, such as New Computer Modern or Computer Modern Unicode. Either \usepackage{newcomputermodern} or \usepackage{libertinus} should do it.

In PDFLaTeX, you need to load the LGR encoding and the textgreek package for this to work:

\documentclass{article}
\usepackage[LGR,T1]{fontenc}
\usepackage{textgreek}

\begin{document}
something something γ something
\end{document}

This gives you a Greek letter as it would appear in an actual Greek word, which might look different from a math symbol.

An alternative way to get the math symbol is to declare the letter active with newunicodechar:

\usepackage{newunicodechar}
\newunicodechar{γ}{\ensuremath{\gamma}}

You could also use 𝛾 (U+1D6FE) for the mathematical symbol, declaring it the same way. This will not conflict with actual Greek text, should you need it.

Answer 2

\documentclass{article}
\usepackage[utf8]{inputenc}
\DeclareUnicodeCharacter{03B3}{$\gamma$}
\begin{document}
something something γ something $\gamma$
\end{document}