As cool as a cucumber and Good-tempered

Good-tempered and as cool as a cucumber are semantically related In some cases you can replace phrase "Good-tempered" with "As cool as a cucumber", this phrases are similar.

Good-tempered adjective - Having an easygoing and pleasing manner especially in social situations.

As cool as a cucumber and good-tempered are semantically related in easy-going topic. Sometimes you can use "As cool as a cucumber" instead an adjective phrase "Good-tempered".