understandable adj.
1 seeming normal and reasonable
VERBS be, seem | become
ADV. very | completely, entirely, perfectly, quite, wholly | fairly
2 easy to understand
VERBS be, seem
ADV. easily, readily Warning notices must be readily understandable.
PREP. to The instructions must be understandable to the average user.
You can also check other dicts: understandable (English, 中文解释 ), wordnet sense, Collins Definition