Tough leather
tough like a diamond
Tough looks
Tough love rarity
Tough luck
Tough luck ... I don't care what you think
Tough march
Tough meat stuff
tough membrane covering the upper part of the cerebellum
tough more-or-less rigid protective covering of an animal or plant
Tough mount to mount
Tough mutt
Tough navy guy
Tough noogies
Tough nut
Tough nut to crack
Tough nuts to crack
Tough on melodists
Tough on the ears
Tough on the nose
Tough on the tongue
Tough on traveling, in a way
Tough one
Tough opponents
Tough or "hot" place
tough or aggressive person
Tough out
tough paperboard made from wood and wastepaper pulp: used for making boxes, etc
Tough part when knitting a sock
Tough period
Tough period of the school year
tough person
Tough person to bargain with
Tough person to get information from
Tough person to tolerate
Tough phrase for an interpreter
Tough phrase for foreigners
Tough pickup for some bowlers
Tough pill to swallow
Tough pills to swallow, at times
Tough pitch to hit
Tough place to be in
Tough place to come out a winner
Tough play for Derek Jeter
Tough poker hand to beat
Tough posers
Tough position
Tough predicament
Tough problem
Tough problem to face?
Tough puff
Tough punk
Tough puzzle
Tough puzzle, informally
Tough puzzles
Tough question
Tough questioning (inf)
Tough questions
Tough request
Tough riddle
Tough rivals
Tough road to hoe
Tough row to ___
Tough row to hoe
Tough rubber?
Tough ruler
Tough shark
Tough shot for a bowler
Tough Situation
Tough situation
Tough situations
Tough skin
Tough skinned
Tough sledding
Tough slog
Tough spot
Tough spot for a golfer
Tough spot for actor Walter?
Tough spot for Daniel
Tough spot to self-trim hair
Tough spots
Tough spots to be in ... or what 17-, 20-, 38- and 53-Across represent?
Tough spots to be in  or what 17-, 20-, 38- and 53-Across represent?
Tough spots to get out of
Tough string
tough stringy animal tissue found in meat
Tough stuff
Tough stuff in meat
Tough stuff to walk through
Tough syndicate
Tough synthetic
tough synthetic substance made from silicon and used in lubricants
Tough tan twill
Tough task
Tough teammate to handle
Tough test
Tough test, as it were
Tough test, informally
Tough test, slangily
Tough tests
Tough tests of knowledge
Tough thing to be in
Tough thing to be put through
Tough thing to be stuck in
Tough thing to crack
Tough thing to fill
Tough thing to kick
Tough thing to master at the Masters
Tough thing to overcome
Tough thing to run on
Tough thing to swallow
Tough things to kick
Tough timber
Tough time
Tough time for Caesar
Tough time for parents
Tough time spent between jobs?
Tough time to farm
Tough times
Tough tissue
Tough to budge
Tough to catch
Tough to clean
Tough to climb
Tough to climb, in a way
Tough to climb, perhaps
Tough to comb
Tough to crack
Tough to cycle on
Tough to dig into, as soil
Tough to drive through
Tough to endure
Tough to fathom
Tough to figure out
Tough to find
Tough to get ahold of
Tough to get hold of
Tough to get through
Tough to get through to
Tough to get up
Tough to get your hands on
Tough to grasp
Tough to hear, as criticism
Tough to hold
Tough to knock out
Tough to learn
tough to masticate
Tough to navigate
Tough to outwit
Tough to resolve
Tough to root out
Tough to see through
Tough to solve
Tough to sort out
Tough to spot, probably
Tough to squeeze through
Tough to take
Tough to titillate
Tough to understand
Tough toenails!
Tough trek
Tough trial
Tough trials
Tough trip
Tough trip-takers
Tough trips
Tough turkey?
Tough turns
tough twill-weave cotton fabric
Tough tyke to handle
Tough type of exam
Tough walk
Tough watchdog
Tough way to learn
Tough way to swim
tough white substance that forms the outer covering of the eyeball
tough wiry grass
Tough wood
Tough work
tough youth
TOUGH youth (sl.)
Tough-as-nails
TOUGH-barked, fiber/fibre-yielding tree
Tough-guy actor Ray
Tough-guy actor Steve who would have fallen for anything?
Tough-guy competition
Tough-skinned creatures
tough-skinned purple grapelike tropical fruit grown in Brazil
Tough-sounding yarn?
Tough-talking coach
Tough-talking radio talk show host
Tough-to-beat card
Tough-to-get-out-of situation
Tough-to-hit tennis shot
Tough-to-ignore feeling
Tough-to-make pool shot
Tough-to-pass driver
Tough-to-pass one
Tough-to-please actress
Tough-to-read writing
Tough-to-remove stain
Tough-to-sculpt part of some Roman statues
Tough-to-win horse racing bet
Tough-wooded conifer
Tough, as a cop
Tough, durable wood
tough, elastic tissue; mostly converted to bone in adults
Tough, fibrous tissue
tough, leathery cloth
Tough, uncompromising sort
Tough, unsentimental type
Tough's partner
Tough's territory
Toughen
Toughen by exposure
toughen by heat
Toughen by heating, as glass
Toughen or harden
Toughen or harden (Var.)
Toughen steel
Toughen up
Toughen using heat
Toughen, as glass
Toughen, as Glass Actor
Toughen, as glass or steel
Toughen, as to hardship
Toughen,as steel
Toughen: Var.
toughened
Toughened up
Toughened, in a way
toughener Steel component
toughening
Toughens
Toughens (oneself)
Toughens by exposure
Toughens up
Toughens, as metal
Tougher competition than you thought
Tougher to cut a path through
Tougher to find
Tougher to locate
Tougher, as a parent
Toughest hit to get in the cycle
Toughest part
Toughest to climb
Toughest to find
Toughie
Toughie for a language learner
Toughies