lompa?[m] [rare] (singular in Spanish) trousers. Syllable inversion and shortening of pantalón, of the same meaning.
luca?[f] an amount of one thousand items (esp. one thousand pesos, or whatever currency unit is in vigour); una luca verde 'one thousand dollars' (lit. 'a green luca'). See also gamba, palo
macana?[f] 1 a bad thing to happen, an inconvenience, a pity (quite standard and accepted by now); 2 a bad thing that has been done, a screwup, a mistake (esp. in the phrase mandarse una macana).
macanudo/a?[adj, interj] (nothing to do with macana) very good (esp. a deal, an arrangement), nice and friendly, open (a person).
mango?[m] 1 fig. a unit of currency, esp. in the phrase No tener un mango 'Not have a (single) mango'. Etymology uncertain, probably related to the fruit of the same name (though not widely known in Argentina at present). 2 [fixed phrase] al mango (of a machine, a domestic appliance, a car, a recorder) at the maximum possible setting (at full speed, at full volume, etc.); saturated, at the most, al palo.
ma' qué?[interj?] [not polite] surely a rapid speech-form of mas, ?qué...? 'but, what...?'. Difficult to explain except with an example: --Fuimos al shopping y... --?Ma' qué shopping, si es un supermercado grande! '--We went to the mall and... --What mall? It's a big supermarket!'. Note: if you can explain this better, tell me! This phrase is plain Italian, though its usage is somewhat different.
metejón?[m] a passion for an object, person or issue; a strong yearning. From meterse 'to get oneself into [a place]' = 'to fall hopelessly in love'. Used as tener un metejón con 'to have a yearning with = for'.
meter?[vt] [fixed phrase] meter la pata 'to get one's leg in', to do something stupid, to make a mistake, to manage a situation badly. Can be completed with hasta el fondo 'down to the bottom' for emphasis.
micro?[m] in Buenos Aires, a bus; in Rosario, a short distance, urban bus, and only if mentioned in the media (the usual word is colectivo or, less commonly, ómnibus).
milico/a?[m, f][slightly derogatory] a member of the millitary. From the beginning of militar 'millitary person' and the seemingly despising suffix -(i)c-.
mina?[f] [Lunfardo] a girl, a woman. Mainstream, standard colloquial way of referring to a female from her teens on. Not rude, but not accepted in formal speech either. Cf Castilian Spanish tía.
minga?[interj] [rather uneducated] of course not! ... Y si me pide otro favor más, ?minga! '... And if he/she asks for any other favor, (I'll tell him/her) of course not!'.
mishadura?[f] [Lunfardo, probably from miseria 'bad economic situation' and dura 'hard'] bad economic situation, esp. when generalized to the whole country; economic crisis, recession, lack of opportunities for employment and trade.
morfar?[v] to eat. From the same root: morfi [n] food, something to eat, a meal.
mufa?1 [f] bad luck, esp. in games and gambling; 2 [m, f, uncountable, no article] a person who brings bad luck, a jinx. (Argentine ex-president Carlos Menem was said to be mufa; whenever he shook hands with an Argentine tennis player or went to see a football match of a favourite team, they lost.)