The Suspicious class, or PIh class, was a type of starship used by the Klingon Empire in the year 2290.

These small ships filled a variety of roles which included; science vessel, troop transport, armored freighter, sensor picket ship and as a battle frigate. It was not a popular design among the Klingons. In addition to this, it was actually an old hull design that dated back to the 2270s. It was noted that there were about three hundred of these starship hulls in service. They were noted on being slow, ponderous despite their small size but did make up for this in terms of firepower as well as its 'flexible' design.

These ships were not as deadly as the infamous B'rel class, which was tasked with replacing the Suspicious class frigates, who lacked photon torpedoes which was another reason why the design was a failure. (TOS video game: Klingon Academy)

Klingon starship classes
Klingonese names	Akif • B'rel • Baka Re' • Ber'taa • Besz Ra'te' • Birok • CharghwI' • Chava'Kal • ChunDab • Chuq'Beh • Chutok • D'aka • D'ama • Dath D'lan • D'esta Kar • D'Gavama • Eakin K'nall • Fek'lhr • Haqtaj • H'ban Pav • Jach'Eng • Jfolokh • Kalath • Karas • Kas Maal • K'el Ri'anda • Kh'exrilin • K'hanakh • Khitomer • Kl'ar • Klolode • Kl'sarza • Kl'xenova • K'mirra • K'nall • K'nel • Koloth • Kom Ka'des • Komo Val • Koreba • Kronos • K't'agga • K't'alla • K't'inga • K't'kara • K't'mara • K't'rika • K'vort • K'vort Cha • L'rexa • Lar'hal • Lara'atan • LI'wI' • Mas To Gal • May'Duj • Mortum Hesta • Na Ra'den • Negh'Var • NuQ'Duj • PIH • Plen Zha • PumwI' • qa'Hos • Qang • Qeh'Ral • Qexa • qeylIS betleH • QuD • Riskadh • Sivista • SuQ'jagh • SuvwI'Qeh • T'h'lar • Talat Kh'exesta • Tas'esta • Vakk • V'al'kon • V'kar Zadan • V's'talo • VoDleH • Voodieh • Vor'cha • Z'gal • Z'gavasta • Z'gavva • Z'mortama • Zha Mortas
Translated names	Accuser • Administrator • Alliance • Battle Cruiser • Bird of Prey • Bringer of Agony • Bringer of Destiny • Bringer of Destruction • Bringer of Justice • Carrier of Doom • Catapult • Chancellor • Death Boot • Death Rite • Death Stalker • Defender • Emperor • Enforcer • Ever Victorious • Fat Man • Great Bird • Grim Reaper • (Gull) • Healer • Insurrection • Little Killer • Luckless • Mender • Mover • (Murph) • One Wing • Painbringer • Pathmaker • Predator • (Raptor) • Ravenous • Relentless • Saber • Seeker • Speedstar • Stalker • Star • Stinger • Stingtongue • Strong Victor • Stronger Bird • Suspicious • Swiftwind • Sword of Kahless • Throne Seeker • Trader's Game • Truthbringer • Tugboat • Unseen Creeper • Warrior's Anger • Watcher • Winner
Alphanumeric names	B5 • D2 • D3 • D4 • D5 • D6 • D7 • (D7/D5 Klolode • D7 Akif • D7A • D7C • D7G • D7M • D7R • D7S • D7 Koloth) • D9 • D10 (bird of prey) • D10 (cruiser) • D11 • D12 (bird of prey) • D12 (cruiser) • D14 • D16 • D18 • D20 • D32 • E4 • E6 • F5 • F5B • F5C • F5G • F5GB • F5K • F5L • F5W • F5Y • F6 • FWK • FWL • FWC • G2 • G3 • G4 • G5 • G6 • G8 • K3 • K4 • K5 • K6 • K14 • K15 • K17 • K18 • K22 • (K22B) • K23 • K24 • K26 • K27 • K30 • K32 • L6 • L9 • L13 • L24 • L42 • S4 • S5 • S8 • T3 • T5 • T12
By time period or type	Birds-of-prey (22nd century bird of prey) • 23rd century scout vessel • mobile battle base • battleship • cargo ship • colony ship • construction ship • dropship • mining freighter • prison barge • repair ship • scout ship