From BiblePortal Wikipedia

Vine's Expository Dictionary of NT Words [1]

1: Διασαφέω (Strong'S #1285 — Verb — diasapheo — dee-as-af-eh'-o )

"to make clear, explain fully" (dia "through," intensive, and saphes, "clear"), is translated "explain" in  Matthew 13:36 RV (AV, "declare") translates phrazo; in   Matthew 18:31 , "told," of the account of the unforgiving debtor's doings given by his fellow-servants. The preferable rendering would be "they made clear" or "they explained," suggesting a detailed explanation of the circumstances.

Webster's Dictionary [2]

(1): ( a.) To flatten; to spread out; to unfold; to expand.

(2): ( a.) To make plain, manifest, or intelligible; to clear of obscurity; to expound; to unfold and illustrate the meaning of; as, to explain a chapter of the Bible.

(3): ( v. i.) To give an explanation.