a heart like a capering monkey and a mind like a galloping horse -- restless; be prone to outside attractions; fanciful and fickle; harbor monkey-feelings and horse-thoughts; in a restless and jumpy mood; One's heart is agile as an ape and one's thoughts swift as a horse.; one who can't settle down to his job; perturbed; the heart of an ape and the mind of a horse; with one's mind running wild; When one means gibbon, he thinks of a horse -- wavering in purpose.; restless and whimsical; unsettled [fickle] in mind