gu-

gu- since g- followed by a vowel in English usually has a "soft" pronunciation, a silent -u- sometimes was inserted between the g- and the vowel in M.E. to signal hardness, especially in words from French; but this was not done with many Scandinavian words where hard "g" precedes a vowel (gear, get, give, etc.). Germanic -w- generally became -gu- in words borrowed into Romance languages, but O.N.Fr. preserved the Frankish -w-, and English sometimes borrowed both forms, hence GUARANTEE (Cf. guarantee)/WARRANTY (Cf. warranty), GUARD (Cf. guard)/WARD (Cf. ward), etc.