In English, for example, I use sensible with the meaning of  sensitive.

sensible (adj.) late 14c., “capable of sensation or feeling;” also “capable of being sensed or felt, perceptible to the senses,” hence “easily understood; logical, reasonable,” from Late Latin sensibilis “having feeling: perceptible by the senses,” from sensus, past participle of sentire “perceive, feel” (see sense (n.)).

Of persons, “aware, cognizant (of something)” early 15c.; “having good sense, capable of reasoning, discerning, clever,” mid-15c. Of clothes, shoes, etc., “practical rather than fashionable” it is attested from 1855.

and

sensitive (adj.), late 14c., in reference to the body or its parts, “having the function of sensation”, also (early 15c.) “pertaining to the faculty of the soul that receives and analyzes sensory information”, from Old French sensitif “capable of feeling” (13c.) and directly from Medieval Latin sensitivus “capable of sensation”, from Latin sensus, past participle of sentire “feel perceive” (like sense (n.)). 

Meaning “easily affected” (with reference to mental feelings) first recorded in 1816; meaning “having intense physical sensation” is from 1849. Original meaning is preserved in sensitive plant (1630s.), which is “mechanically irritable in a higher degree than almost any other plant” (Century Dictionary). Meaning “involving national security” is recorded from 1953.

Other Middle English senses included “susceptible to injury or pain” (early 15c., now gone with sensitive); “worldly, temporal, outward” (c. 1400); “carnal, unspiritual” (early 15c., now gone with sensual). Related: Sensibleness.

When looking at the meanings of sensible and sensitive in English, French and Italian for example, I think it is clearer why I tend to mis-use the term in English.

In French, sensible is equivalent to the English sensitive. This is the explanation from the Larousse :

• Qui est, qui peut être perçu par les sens : Le monde sensible.
• Qui est apte à éprouver des perceptions, des sensations : Avoir l’oreille sensible.
• Qui est très facilement affecté par la moindre action ou agression extérieure : Être sensible de la gorge. Une dent sensible au froid.
• Se dit d’une partie du corps que l’on ressent, qui est plus ou moins douloureuse : La douleur est moins vive, mais la zone est toujours sensible.
• Qui éprouve facilement des émotions, des sentiments, notamment de pitié, de compassion : Une nature sensible. Être sensible à la douleur d’autrui.
• Qui est particulièrement accessible à certaines impressions d’ordre intellectuel, moral, esthétique ; réceptif : Être sensible aux compliments.
• Se dit d’un appareil, d’un instrument de mesure, qui obéit à de très légères sollicitations : Une balance très sensible.
• Se dit d’un matériel, d’un produit qui est sujet à des variations de prix dépendant de facteurs extérieurs.
• Que l’on doit traiter avec une attention, une vigilance particulière : Dossier sensible.
• Qui fait l’objet d’une surveillance renforcée pour des raisons de sécurité : Vol sensible.
• Qui est facilement perçu par les sens ou par l’esprit : Une sensible différence de prix.
• Se dit d’une émulsion photographique, d’un explosif, d’un matériel, etc., doués de sensibilité.

Whereas French sensitif means sensory or oversensitive in English. As, like Larousse says: Sensitif se dit d’un sujet doué de perception extrasensorielle. 

For some time I also used the term “awful” in its etymological way, i.e. “worthy of respect or fear”, and not with its actual meaning “very bad”. Especially when reacting spontaneously to an awesome situation, it happened that I said awful, not intending it in the modern way, but in the medieval way:

awful (adj.): c.1300, agheful “worthy of respect or fear”, from aghe  an earlier form of awe (n.) + ful. The Old English word was egefull. Weakened sense “very bad” is from 1809; weakened sense of “exceedingly” is by 1818.

Do you also use a word in its etymological way or with the meaning it has in another language? Please share in the comments.