Prefix that intensifies or adds a sense of excellence; limited to a few fixed compounds such as いち早く (very quickly) and 逸物 (excellent thing). Not freely productive.
I rushed to the scene very quickly.
This sword is truly an excellent piece.
excellent article; fine item; masterpiece; gem
miss; lose (a chance) · overlook; omit; forget · deviate; depart from the norm
loss; losing
escape; leaving; breaking out · excelling; preeminence; standing out
anecdotal history; historical anecdotes
lost book; missing book
missing a chance; letting an opportunity slip
first-rate specimen; superb item; excellent person
muffed ball; error
escape; flight; running away · running off the track
swiftness; fleetness of foot; swift horse · outstanding talent; person of great talent
extraordinary person; exceptional individual
The prefix いち is of uncertain origin; it may be related to the number 一 (いち, 'one') with a sense of 'first' or 'best', but the exact derivation is unclear. The kanji 逸 is ateji.