Something is abandoned if if has been left alone and forsaken, with nobody caring for it or paying it attention. The shopping cart in the picture has been abandoned.
Something is abrasive if it is used to grind or polish something else. A good example of something that is abrasive is sandpaper.
Something that is absorbent will soak up any liquids it comes into contact with. Sponges are absorbent.
Art is abstract if it has been derived, or abstracted from something real but doesn't bear a close resemblance to what it is supposed to represent, like more traditional art does. Some parts of the art might be recognisable, some exaggerated, some downplayed. Abstract art can be so stylised you can't even recognise what it is, so sometimes when you look at an abstract picture or sculpture you can't tell what it is a picture or sculpture of.
Academic describes something that is educational or related to school. If learning and studying are easy for a student, she can be described as academic.
Something is acidic if it can be used as an acid. Many common things are acidic. Lemon and orange juice are quite acidic.
Something is acoustic if it relates to sound. For example, the picture is of acoustic insulation, which is used to dampen sound in places like recording studios. Musical instruments that are not electronically enhanced are called acoustic instruments.
Adrift means something, such as a boat, is lost, abandoned, or floating freely in water without an anchor.