According to SOWPODS (the combination of Scrabble dictionaries used around the world) there are 47 words with the pattern --I-G. That is, five letter words with 3rd letter I and 5th letter G. In alphabetical order, they are:
acing
aging
ahing
aking
aping
awing
axing
being
bling
boing
bring
cling
cuing
doing
duing
dying
ehing
eking
ering
exing
eying
fling
going
hoing
hying
icing
iring
kaing
klieg
lying
nying
ohing
oping
owing
piing
pling
ruing
sling
sting
suing
swing
thing
toing
tying
using
vying
wring
tiptoes
geneticsenatorlengthsjanitormonitormonster
boxtops
bladderblessedblubberbraggedbrittlechannelchappedchoppedchippedchipperclipperclutterdresseddrippeddribbledroppedflaggedflannelflapperflatterflippedflipperfloppedflossedflutterglitterglossedgrammargriddlegrilledgrippedplatterprattlepressedquibblequitterscatterscuffleshelledshimmershippedshoppedshoppershuddershuffleshuttleskippedskipperslappedslippedslippersmelledsmugglesnugglesnapperstammersteppedstiffedstifferstoppedstopperswimmerthinnertrappedtrimmertrippedtwitter
spotted, between
startle
Chasten
abdomen abysmal
pointer
One example of a seven-letter word with a 'u' as the fifth letter is "culture." Another example is "trusted." These words follow the pattern of having the letter 'u' in the fifth position while being seven letters long.
Some seven letter words with N as the fifth letter areagainstbalancefriendspartnerqueenlyscienceseventy
amorous