Synonyms for Bottleneck:

adj.

hindering (adjective)
constipating, Obstructing, Tangling, Encumbering, restricting, Damming, inhibiting, hindering, Cramping, constraining, Entangling, Resisting, Snagging, Crimping, crippling, thwarting, Deterring, blocking, impeding, Restraining, choking, congesting, Complicating, Fouling, Handicapping, Snarling, baffling, Delaying, burdensome, Detaining, Entrapping, Clogging, frustrating.

n.

congestion charge, gridlock, filter, bumper-to-bumper, hold up, back up, busy. inconvenience, predicament, problem, embarrassment. bottleneck (noun)
constriction.
focus (noun)
forum, epitome, core, meat, funnel, nucleus, hub, magnet, plenum, crux, marrow, soul, asymptote, kernel, axle, essence, intersection, lodestar, focus, crossing, rendezvous, lure, polestar, spirit, center, gathering, rally, heart.
hindrance (noun)
disadvantage, barrier, impasse, restriction, inhibition, restraint, impedance, entrapment, hurdle, deterrent, drawback, complication, frustration, entanglement, interruption, damper, constipation, stoppage, impediment, blockade, blockage, obstruction, obstacle, resistance, congestion, constraint, opposition, encumbrance, bafflement, hindrance.
obstacle (noun)
clog, snag, obstruction, jam, impediment, congestion, hindrance, blockage, block, barrier.
shape (noun)
constriction.

v.

hinder (verb)
foul, restrict, jam, hinder, complicate, fetter, snarl, burden, deter, curb, oppose, catch, mire, cramp, congest, brake, obstruct, encumber, entangle, frustrate, snag, resist, impair, crimp, constrain, thwart, hamstring, check, cripple, interrupt, dam, detain, delay, stay, hamper, baffle, bar, tangle, plug, counter, bung, paralyze, choke, restrain, block, stop, impede, handicap, constipate, inhibit, clog, drag, entrap.

Other synonyms:

gridlock, bumper-to-bumper, congestion charge. hold up. busy. filter. back up. Other relevant words:
constriction, hold up, bumper-to-bumper, problem, gridlock.