Does this mean the man has a weight of 70 kg, that he is measuring out 70 kg of something (as in "he weighs 70 kg of sugar"), or both?
The usage is exactly the same as in English - it can mean both.
Mheáigh sé an bosca. mheáigh sé 20kg - "He weighed the box. It weighed 20kg"
The NEID entry for "kilo" only offers cileagram in Irish:
"it weighs two kilos" - meánn sé dhá chileagram, tá dhá chileagram meáchain ann
"it costs 5 euro per kilo" - cosnaíonn sé 5 euro an cileagram, tá 5 euro in aghaidh an chileagraim air
"a kilo of flour" - cileagram plúir
"a five-kilo bag" - mála cúig chileagram
BUT it also offers fuair mé €5 an kilo agus lena chois, fuair mé €5 an kilo agus tuilleadh for "I got €5 a kilo and up"
"Meánn" doesn't seem to fit either of the two conjugation types exactly. What is the stem and what is the ending that has been added? GRMA.
Meáigh is the verb, igh is removed and nn is added. I'm no expert but this is how I worked it out. A more enlightened answer may make its way to you. Go n-éirigh an bothar leat.