Off-the-wall and Wacko

Off-the-wall adjective - Different from the ordinary in a way that causes curiosity or suspicion.

Wacko and off-the-wall are semantically related. In some cases you can use "Wacko" instead an adjective phrase "Off-the-wall".

Wacko adjective - Having or showing a very abnormal or sick state of mind.

Off-the-wall and wacko are semantically related. Sometimes you can use "Off-the-wall" instead an adjective "Wacko".