Definition: Given the Question and Answer pair, detect whether the answer is acceptable or not. Denote acceptable answer as "yes", otherwise denote as "no". An acceptable answer is consistent with the context in question, detailed, long, and uses general knowledge of English. Answers that are not definite and suggest a variety of options are not acceptable answers.
Input: Question: I'm having a serious argument with a friend on the status of the word "suck" when I used it about him by saying "You suck!" because he missed a train. We are both non-native English speakers. He claimed that I used it as a foul or slang term. I vehemently disagreed with him about it. I told him that the word "suck" can be used to describe something inefficient or not good enough as well like it is used in the example "Samsung mobile sucks". Am I right to describe the use of the word "suck" in such context? 
Answer: Yes, as used in the OP, "sucks" is always slang. SUCKS transitive verb; slang: a. To be highly unpleasant or disagreeable: This job sucks. b. To be of poor or inferior quality: The acting in that movie sucked. c. To be inept: I suck at math. see TFD The fixed-phrase "this/that SUCKS dick/cock" gained currency exclusively among male American youth in the early 1970's as a derogatory slang expression of general contempt for some object, activity, or person. The phrase was, as intended, unapologetically misogynistic and homophobic. In the seventies, female youth never employed this idiom. No surprise there, though this is no longer the case. By the late seventies, probably in order to evade adult censure (and since youth knew precisely what was intended), the last word of the phrase was dropped. If the term is currently considered to be non-vulgar it is most likely due to this partial sanitization and because contemporary youth are ignorant of the original misogynistic and homophobic intent. see, ELU; UE;.

no