Adjective: Safe, secure, comfortable.
Turvallinen is often seen in its partitive form, turvallista, as in ”Tätä on turvallista syödä” (”it’s safe to eat this”) though in our example today, since it is directly modifying koti (”home”) it is in nominative.
Turvallinen comes from turva (”safety”) plus the suffix –llinen, a denominal suffix that is used to form adjectives indicating possession. I.e., turvallinen is a word describing something possessing the quality of safety.
Antonyms are vaarallinen (”dangerous”) and turvaton (”insecure,” ”unsafe.”)