combustible
From LSJ
ἔνδον σκάπτε, ἔνδον ἡ πηγὴ τοῦ ἀγαθοῦ καὶ ἀεὶ ἀναβλύειν δυναμένη, ἐὰν ἀεὶ σκάπτῃς → Dig within. Within is the wellspring of Good; and it is always ready to bubble up, if you just dig | Look within. Within is the fountain of the good, and it will ever bubble up, if thou wilt ever dig.