No problem is an English expression, used as a response to thanks (among other functions). It is regarded by some as a less formal alternative to you're welcome, which shares the same function.
In the culture of younger Americans, no problem is often used as a more conversational alternative to you're welcome.[1]
It is widely believed that younger speakers especially favor no problem over you're welcome, and empirical research has corroborated this belief.[2]
"No problemo" is "a popular elaboration" of "no problem" also used and popularized in North American English.[3]
The expression is sometimes used as an instance of "pseudo-Spanish" or Mock Spanish.[4] An early example appears in a 1959 edition of the American Import and Export Bulletin, with an advertisement stating: "Foreign shipping is No Problemo".[5] Its usage as a Spanish expression is incorrect; a correct translation would be Spanish; Castilian: ningún problema, Spanish; Castilian: sin problema or Spanish; Castilian: no hay problema. Many Spanish words from Latin roots that have English cognates have an -o in Spanish from the masculine Latin suffix -us, such as "insect" (Spanish; Castilian: insecto), "pilot" (Spanish; Castilian: piloto), and "leopard" (Spanish; Castilian: leopardo); however, "problem" belongs to the group of words ending with an a in Spanish that have a similar English counterpart, such as "poet" (Spanish; Castilian: poeta), "ceramic" (Spanish; Castilian: cerámica) and "rat" (Spanish; Castilian: rata). In the case of Spanish; Castilian: problema, this is because it has a Greek 'ma' ending, and as such is among the Iberian words ending in 'ma', such as tema, which is in fact masculine.