It's suck! / When markets mature

What does it mean when someone says, "It sucks"?  Is it impolite? 

Naowarat Prirakit

The verb "to suck" means to take liquid into the mouth between pursed lips, like when you drink through a straw:

The baby must have been very hungry; it sucked the bottle empty in no time.

See the guy in the last row sucking on his pencil?  That's Sam.

But when someone says something or a situation "sucks", he means it is bad or unpleasant.  It is American slang and okay to use among friends. You should not use it in formal situations:

Mr Brainworth told me to finish all my assignments today or he would give me a written warning, which means I can't go to James' birthday party.  That sucks, doesn't it?

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Dear Dr English,

How should I translate the word "mature" in the following sentence?  "As the travel market matures, companies are offering a mixture of guided and do-it-yourself tours."  Thank you very much for your help. 

Suwanne Mekumphan

When used with a child or young animal,  "to mature," means to develop into adulthood. Or when we describe a person as mature, he or she is fully developed and possesses a balanced personality and emotional behaviour. 

But the sentence in question is about a market in tourism.

In this sense, "mature" describes the situation in which something has been fully developed; as the travel market has fully developed, companies are offering a mixture of guided and do-it-yourself tours.