It simply means, not suitable or not fit.

It is estimated that it takes an average of one to two years to receive a suitable donor lung, and the wait is made less predictable by the necessity for tissue match.

Any of the soft, fast growing trees that are grown in sustainable forests, are suitable.

Aries and Cancer are cardinal signs, but for two people to be a suitable match for each other it's not only the Sun signs that should be taken into consideration. The other planets, aspects and houses have to be considered too.

A matchstick is a small wooden stick or stiff paper coated with material that can be ignited by striking the match against a suitable surface. The match head usually contains phosphorus or phorphorus sesquisulfide.